OBD-II Code C1093: Brake System Malfunction

What Does C1093 Mean?

Code C1093 indicates the vehicle's computer detected a critical failure within the Anti-Lock Brake System (ABS). The system received an illogical signal regarding brake pressure or component status, immediately disabling safety features like ABS, traction control, and stability control.

Technical definition: C1093 definitions vary by manufacturer but typically indicate a 'Hydraulic Control Unit (HCU) / ABS Module Internal Failure' or a 'Pressure Sensor Signal Plausibility Failure'. The code almost always includes a two-digit suffix. Suffix '-62' indicates a 'Signal Compare Failure' where the module's internal self-checks fail. Suffix '-64' points to a 'Signal Plausibility Failure', where sensor readings contradict vehicle behavior (e.g., the vehicle decelerates without brake pressure applied).

Can I Drive With C1093?

No — Do Not Drive. Do not drive the vehicle. Your Anti-Lock Braking (ABS) and stability control systems are disabled, dramatically increasing the risk of skidding during hard braking. On recalled 2018-2019 Jeep and Dodge models, a severe rollaway risk exists because the vehicle can be shifted from 'Park' without pressing the brake pedal. The immediate safety risks far outweigh any potential for component damage.

Common Causes

• Internal ABS/Hydraulic Control Unit (HCU) Failure (Very Common) — This is the primary cause, especially on Jeep and Dodge models where it is a known defect. The electronic brain or hydraulic pump fails internally, sending false signals and disabling the system.
• Faulty DSC/Traction Control OFF Switch (Common) — On Mazda models, a faulty 'Dynamic Stability Control (DSC) OFF' switch that shorts or sticks sends a continuous 'ON' signal for more than 5 seconds, triggering this code.
• Faulty Wheel Speed Sensor / Hub Bearing Assembly (Common) — The wheel speed sensor is integrated into the wheel hub bearing assembly on modern vehicles. Corrosion or physical damage causes an open or shorted signal, triggering ABS faults.
• Low or Contaminated Brake Fluid (Less Common) — Low or moisture-contaminated brake fluid alters hydraulic pressure readings, causing the system to report a plausibility failure (often indicated by a -64 suffix).
• Air in the Brake Lines (Less Common) — If the brake system was recently serviced and improperly bled, trapped air causes pressure sensor readings that contradict the vehicle's deceleration rate.
• Blown ABS System Fuse (Rare) — A blown fuse for the ABS pump or control module cuts power to the system. This usually results from an underlying electrical short in the pump motor.
• Wiring Harness or Connector Damage (Rare) — Corrosion or physical impact damages the wires providing power, ground, or communication signals to the ABS module, mimicking a complete module failure.

Symptoms

• ABS, Traction, and Brake Warning Lights Illuminated — The dashboard will simultaneously display warning lights for the ABS, Traction Control (ESC/DSC), and general Brake systems.
• Brake Lights Stay On Constantly — On affected Jeep and Dodge vehicles, the exterior brake lights remain illuminated even when the brake pedal is not pressed.
• Can Shift Out of Park Without Braking — A dangerous rollaway risk occurs on specific FCA models where the transmission can be shifted out of 'Park' without driver brake input.
• Hard or Spongy Brake Pedal — The brake pedal feels unusually hard or spongy due to internal valve failures within the hydraulic control unit.
• Advanced Safety Systems Disabled — Systems relying on the ABS module, such as Adaptive Cruise Control (ACC) and Forward Collision Warning, are completely disabled.
• Erroneous Speedometer Reading — If the root cause is a faulty wheel speed sensor that supplies data to the instrument cluster, the speedometer behaves erratically or drops to zero.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this code.

Common Fixes & Costs

• Replace ABS Module / Hydraulic Control Unit (HCU) — Parts: $400-$900, Labor: $250-$450, ~2.5 hr book time (Professional)
• ABS Module Repair/Rebuild Service — Parts: $150-$350, Labor: $150-$300, ~2 hr book time (Intermediate)
• Replace DSC/Traction Control OFF Switch — Parts: $40-$100, Labor: $50-$150, ~0.8 hr book time (DIY)
• Replace Wheel Hub Bearing Assembly — Parts: $90-$250, Labor: $150-$300, ~1.5 hr book time (Intermediate)
• Brake Fluid Flush and Bleed — Parts: $20-$40, Labor: $100-$200, ~1 hr book time (Intermediate)
• Replace Blown Fuse — Parts: $1-$5, Labor: $0-$50, ~0.1 hr book time (DIY)

Used vs. New Parts: Buying Guide

When a used part is worth it: A used ABS module makes sense for older vehicles (10+ years) where a new part is discontinued or prohibitively expensive. Match the part number exactly and source from a reputable seller.

Donor-vehicle mileage cap: roughly under 100000 miles for the part to have meaningful remaining life.

Donor quality checklist:

• Verify the part number is an exact match for your original module.
• Purchase from a supplier offering at least a 30-90 day warranty.
• Avoid parts from flood-damaged or heavy-corrosion vehicles.
• A used module requires professional programming ('Proxy Alignment') to your car's VIN.

Decision logic:

• If Vehicle is under recall for this issue (e.g., 2018-2019 Jeep/Dodge) → Get a new part installed for free at the dealership.
• If A reputable rebuild service is available for your specific module → Rebuild your original module; it is cost-effective and avoids programming issues.
• If Vehicle is newer and the budget allows → Buy new OEM for maximum reliability and warranty.
• If Part is discontinued and no rebuild service exists → A tested, warrantied used part is your only option. Factor in the cost of professional programming.

Warranty tradeoff: Used parts typically come with a 30-day to 1-year warranty. Aftermarket new parts have a 1-3 year warranty. Rebuild services offer warranties from 1 year to lifetime. OEM parts carry a 1-2 year warranty.

Worst-case if a used part fails: $300-$600 if a used part is defective, covering repeat labor for installation and programming attempts.

What Happens If You Wait — Timeline

1. 0-1 month: ABS, ESC, and Brake warning lights illuminate. Safety systems are disabled. On recalled Jeep/Dodge models, brake lights stick on and the vehicle is shiftable from Park without braking, creating an immediate rollaway risk. (MPG impact: 0%% · Added cost: $0-$300 (Cost of a new battery if drained by stuck-on brake lights).)
2. 1-6 months: Continued driving without ABS increases accident risk. In a panic stop, wheels lock, causing flat spots on tires. The brake pedal feels unresponsive as internal hydraulic seals degrade. (MPG impact: 0%% · Added cost: $150-$800 (Cost of replacing tires due to flat-spotting from locked-up brakes).)
3. 6-12 months: Internal corrosion from old brake fluid worsens, seizing valves within the HCU. If the ABS pump motor runs continuously, it burns out, making a simple module rebuild impossible. (MPG impact: 0-2%% · Added cost: $500-$1000 (Difference in cost between a module rebuild and a mandatory full HCU assembly replacement).)
4. 12+ months: Catastrophic failure of the HCU leads to internal fluid leaks or a complete loss of hydraulic pressure to one or more brake circuits. The vehicle is a severe safety hazard. (MPG impact: 0-2%% · Added cost: Cost of an accident.)

Cost of Not Fixing It

• Immediate: Loss of ABS, traction control, and stability control, significantly increasing the risk of skidding and collision in emergency braking. (Added cost: Cost of an accident.)
• 0-1 month: On recalled Jeep/Dodge models, a rollaway risk exists. Brake lights stay on, draining the battery and confusing other drivers. (Added cost: $100-$300 (for a new battery if drained completely).)
• 1-6 months: Continued driving without ABS leads to uneven tire wear or flat-spotting if wheels lock up during braking. (Added cost: $150-$400 (per tire for premature replacement).)
• 6+ months: If the ABS pump runs constantly, the motor burns out, requiring full HCU assembly replacement rather than a simpler module repair. (Added cost: $500-$1000 (difference between a module rebuild and a full assembly replacement).)

Diagnosis Steps

1. Read the Full Code with a Professional Scanner
   Basic OBD-II readers cannot read 'C' codes or their two-digit suffixes. Use a professional-grade scanner to retrieve the full C1093-XX code to pinpoint the exact failure type.
   Tools: ['Professional Bi-Directional Scan Tool'] (Intermediate)
2. Check for Recalls and Technical Service Bulletins (TSBs)
   Enter your vehicle's VIN on the NHTSA website. Major safety recalls (NHTSA #24V838000) exist for this code on 2018-2019 Dodge and Jeep models, entitling you to a free dealer repair.
   Tools: ['Smartphone or Computer', 'Vehicle VIN'] (Beginner)
3. Inspect Brake Fluid Level and Condition
   Check the brake fluid reservoir. Ensure the fluid level is between the 'MIN' and 'MAX' marks and the fluid is clear or light amber. Dark, murky fluid causes hydraulic performance issues.
   Tools: ['Flashlight', 'Clean rag'] (Beginner)
4. Inspect ABS Fuses
   Locate the engine bay and cabin fuse boxes. Test all fuses related to the ABS pump and module for continuity.
   Tools: ['Fuse puller', 'Multimeter'] (Beginner)
5. Monitor Live Sensor Data (Jeep/Dodge Specific)
   For code C1093-62, monitor live data PIDs $2002 (Primary Pressure Sensor value) and $2007 (Primary Pressure Sensor offset). A significant non-zero offset without the brake pedal pressed confirms an internal module fault.
   Tools: ['Professional Bi-Directional Scan Tool'] (Advanced)
6. Test the DSC OFF Switch Circuit (Mazda Specific)
   Disconnect the DSC OFF switch and the ABS module. Check for continuity between the module connector terminal and a chassis ground. Resistance under 1.0 Ohm indicates a short to ground.
   Tools: ['Multimeter', 'Vehicle-specific wiring diagram'] (Advanced)
7. Verify Power and Ground at ABS Module
   Disconnect the ABS module. Test for battery voltage (12.0-12.6V) at the power-in pins and check for continuity to ground (<0.5 Ohms) at the ground pins. Lack of power or ground indicates a wiring issue, not a module failure.
   Tools: ['Multimeter', 'Vehicle-specific wiring diagram'] (Advanced)
8. Test Wheel Speed Sensor Resistance
   Disconnect the suspected wheel speed sensor harness. Measure resistance between its two pins. A reading of infinite resistance (OL) indicates an open circuit, while near zero indicates a short.
   Tools: ['Multimeter', 'Jack and jack stands'] (Intermediate)
9. Visually Inspect the ABS Module and Wiring
   Locate the ABS module in the engine bay. Inspect the main electrical connector for corrosion or damage, and check nearby wiring for cuts or fraying.
   Tools: ['Flashlight'] (Beginner)
10. Perform ABS Initialization / Self-Test
    Use a bi-directional scanner to perform the 'ABS Initialization' routine. Software glitches occasionally trigger this code, and re-initializing the module resolves it without parts replacement.
    Tools: ['Professional Bi-Directional Scan Tool'] (Intermediate)

When This Code Triggers (Freeze-Frame Conditions)

• Vehicle Speed: 0 mph (The ABS module performs a self-test when the ignition turns on, triggering the code before the vehicle moves.)
• Brake Pedal Position: Not Pressed (The fault, especially C1093-62 on Jeeps/Dodges, is due to an internal pressure sensor offset present even with no braking.)
• System Voltage: 11.5-14.5V (Normal operating voltage. The code is caused by an internal module or sensor circuit fault, not low voltage.)
• Time Since Ignition On: 1-10 seconds (The code sets very quickly after startup as the ABS module fails its initial self-check.)

Related Codes

• C2200 — Indicates 'Anti-Lock Brake Module Internal' failure. C1093-62 is often a more specific version of C2200. If both are present, it strongly confirms the ABS module has failed.
• U0415 — Means 'Invalid Data Received From ABS Module'. This is a secondary code set by other modules when the ABS module sends nonsensical information due to its internal failure.
• C1095 — Indicates 'ABS Pump Motor Circuit Failure'. If present alongside C1093, it confirms a complete failure of the pump and module assembly.
• C2206 — Indicates 'Vehicle Configuration Mismatch'. Appears after a new, unprogrammed ABS module is installed, confirming the need for a 'Proxy Alignment' procedure.

Climate & Environmental Factors

• High Humidity / Water Exposure: Moisture seeps past failing seals and corrodes the internal circuit board, leading to electrical shorts and module failure.
• Road Salt (Cold Climates): Road salt accelerates corrosion on the ABS module housing, electrical connectors, and wheel speed sensor wiring harnesses.
• Thermal Cycling (Extreme Temperatures): Constant heating and cooling in the engine bay stresses electronic components and solder joints, eventually causing microscopic cracks and circuit failures.

How to Talk to a Mechanic About This Code

Say this: "I have an ABS light on and a C1093 code. I need a diagnostic appointment with a technician who can read manufacturer-specific chassis codes, including the two-digit suffix. For my [Vehicle Make/Model], I know this could be anything from a recall issue to a simple switch, so I want to avoid replacing the whole ABS module without a proper diagnosis."

This signals you are an informed customer. It directs the shop to perform a specific, advanced diagnosis rather than starting with guesswork, discouraging the upselling of unnecessary parts.

Avoid saying:

• 'My ABS light is on, can you fix it?'
• 'Just do whatever it takes to get the light off.'
• 'My brakes feel weird.'

Questions to ask before authorizing the repair:

• What was the specific suffix code (e.g., -62, -64) that you found?
• If recommending an ABS module replacement, did you confirm good power and ground at the module connector?
• Does your estimate for the module replacement include the cost of programming (Proxy Alignment) and the specialized ABS bleed procedure?
• For a Mazda, did you test the DSC OFF switch and its circuit before condemning the ABS module?
• What is the warranty on the recommended parts and labor?

Where to Take It: Dealer vs Independent vs Chain

• Dealer:
  Best for: Vehicles under recall (e.g., 2018-2019 Jeep/Dodge) for a free repair., Complex programming like 'Proxy Alignment' on newer FCA vehicles., Vehicles still under warranty.
  Downsides: Highest labor rates., May refuse to install customer-supplied or rebuilt parts., Less likely to explore non-standard repairs. (Typical cost: +50% vs. baseline)
• Independent Shop: Best overall fit for most out-of-warranty vehicles, provided the shop is well-equipped with modern, bi-directional scan tools.
  Best for: Out-of-warranty vehicles where cost is a factor., Diagnosing common vehicle-specific issues (e.g., BMW E46, Mazda DSC switch)., Installing rebuilt or used ABS modules.
  Downsides: Quality and diagnostic tool capability vary widely; must vet the shop., May not have access to the latest manufacturer software for programming. (Typical cost: +0% vs. baseline)
• Chain Shop: AVOID. The risk of misdiagnosis and improper repair is very high for code C1093.
  Best for: Simple brake jobs (pads/rotors) on cars with no warning lights.
  Downsides: Technicians often lack advanced training for complex electronic diagnostics., Unlikely to have manufacturer-specific scan tools for programming or ABS bleeding., High pressure to upsell leads to misdiagnosis and unnecessary parts replacement. (Typical cost: -10% vs. baseline)

When to Walk Away From the Repair

If the estimated repair cost for the C1093 fault exceeds 50% of the car's current private-party market value, consider selling the vehicle as-is.

• Car worth $4000, fix is $1800: Walk away. The repair cost is approaching half the vehicle's value, and a car with a known safety system fault is difficult to sell.
• Car worth $15000, fix is $1800: Fix it. The repair cost is a small fraction of the car's value and is necessary for safety and resale.
• Car worth $8000, fix is $350: Fix it. If the diagnosis points to a cheaper fix like a DSC switch or a rebuild service, the repair is easily justified.

What Scan Tool You Need for This Code

Minimum: A scanner that reads and clears Anti-Lock Brake System (ABS) / Chassis codes. A basic engine-only code reader is not sufficient.

A standard $20 scanner will not see 'C' (Chassis) codes like C1093. You need a tool that communicates with the ABS module and shows the two-digit suffix (e.g., -62, -64) to pinpoint the true cause.

Budget: BlueDriver Pro or ANCEL FX2000 (~$100) — Reads and clears ABS codes on many popular makes, confirming the C1093 code exists. Unlikely to show manufacturer-specific suffix codes or perform advanced functions.

Mid-range: Foxwell NT630 Plus or Autel MaxiCheck Series (~$150) — Reads/clears ABS codes, shows suffix codes, graphs live sensor data, and performs the 'ABS Auto Bleed' function required after replacing a hydraulic component.

Professional: Autel MaxiCOM MK808S or XTOOL D8S (~$450-900) — Provides full bidirectional control to test individual ABS solenoids. Critically, these tools have the 'Proxy Alignment' function required to program a new ABS module.

Rent vs buy: Buy. Free rental tools from auto parts stores are basic engine code readers and cannot diagnose ABS faults. A mid-range tool is necessary for any parts replacement.

How to Clear the Code After You Fix It

1. Use a professional OBD-II scan tool to clear the Chassis (C) codes from the ABS module.
2. Perform a 'Proxy Alignment' or 'ABS Initialization' if the module was replaced.
3. Perform the 'ABS Service Bleed' procedure with the scan tool if the hydraulic unit was replaced or lines were opened.
4. Perform a test drive including several moderate stops to allow the system to verify the repair.

Drive cycle (~15 minutes): Start the vehicle and idle for 1 minute. Drive in mixed conditions for 10-15 minutes, exceeding 20 mph. Perform several normal stops. The ABS light should remain off. For some vehicles, simply driving for a few minutes allows the system to self-verify and extinguish the light.

Readiness monitors affected: This is a Chassis code and does not affect emissions readiness monitors.

Watch out for:

• Disconnecting the battery will not clear a hard C-code from the ABS module.
• Failing to perform the Proxy Alignment after module replacement results in a C2206 code and continued system malfunction.
• Forgetting to perform the scan tool-actuated ABS bleed procedure leaves air trapped in the HCU, resulting in a spongy pedal.

Will This Fail Emissions / State Inspection?

Yes — this code typically fails an OBD-II emissions inspection.

• California: An illuminated ABS warning light is grounds for failing the safety portion of the inspection.
• New York: An illuminated ABS warning light is grounds for the vehicle to fail the safety inspection.
• Texas: The safety inspection requires that the ABS warning light is not illuminated. If the light is on, the vehicle fails.

Most Commonly Affected Vehicles

• Jeep Grand Cherokee (2018-2021) — Extremely common issue due to internal ABS/HCU module failure. 2018-2019 models are the primary focus of safety recall NHTSA #24V838000.
• Dodge Durango (2018-2022) — Shares the faulty ABS/HCU module with the Grand Cherokee. 2018-2019 models are covered by safety recall NHTSA #24V838000. Repair requires module replacement and 'Proxy Alignment'.
• Mazda MX-5 Miata (NC), Mazda3 (2006-2015) — Prone to setting C1093 due to a faulty or stuck Dynamic Stability Control (DSC) OFF switch or a short in its circuit.
• BMW 3-Series (E46), 5-Series (E39), 7-Series (E38) (1998-2006) — The 'trifecta' of ABS, DSC, and Brake warning lights is often caused by an internal failure of the DSC module's circuit board. Rebuilding the module is a common fix.
• Chevrolet Silverado, Colorado (2014-2019) — ABS and Stabilitrak warnings are triggered by faulty wheel speed sensors, a bad ground connection to the ABS module, or internal module failure.
• Kia / Hyundai Optima, Sonata (2015-2020) — A common cause for ABS/Traction lights is a failed wheel speed sensor integrated into the rear wheel hub bearing assembly.
• Jaguar X-Type, XK8, XJ8 (2002-2008) — C1093 is often a precursor to C1095 (ABS Pump Motor Circuit Failure), pointing to a failing ABS module due to solder joint failure.
• Ford Focus (2005-2011) — This code points to a general ABS system malfunction, frequently traced to the ABS control module itself or a faulty wheel speed sensor circuit.

Manufacturer-Specific Notes

• Stellantis (Jeep, Dodge, Chrysler): Code C1093-62 is the subject of NHTSA recall #24V838000. It indicates internal ABS module failure, causing symptoms like brake lights staying on. Repair is free for affected 2018-2019 models.
• Mazda: C1093 often points to a problem with the 'DSC OFF' switch circuit, not the ABS module. The cause is usually a stuck switch sending a continuous signal or a short to ground.
• General (with C1093-64 suffix): The suffix '-64' translates to 'Signal Plausibility Failure'. The ABS module sees deceleration but no brake pressure, suggesting a problem with the pressure sensor, fluid, or air in the system.

Real Owner Stories

2018 Jeep Grand Cherokee at 75K miles

ABS, ESC, and Brake warning lights illuminated simultaneously. Brake lights stuck on, and the vehicle shifted out of Park without braking.

What they tried:

1. Suspected a faulty brake light switch.
2. Researched symptoms and found C1093-62 is a known recall issue.
3. Took the vehicle to a dealership.

Outcome: Dealer confirmed C1093-62 and replaced the ABS/HCU module for free under safety recall NHTSA #24V838000.

Lesson: For 2018-2019 Jeep/Dodge vehicles, check for recalls before attempting repairs. Do not waste money replacing the brake light switch.

2010 Mazda 3 at 110K miles

DSC and traction control lights stayed on permanently. Code reader showed C1093.

What they tried:

1. Feared an expensive ABS module replacement.
2. Researched Mazda forums and learned about the DSC OFF switch issue.
3. Disconnected the switch; the code did not return after clearing.

Outcome: Replacing the faulty DSC OFF switch (a $60 part) permanently fixed the issue in under an hour.

Lesson: On Mazda vehicles, C1093 is frequently caused by a cheap dashboard switch, not the ABS module.

2002 BMW 325i (E46) at 150K miles

The 'trifecta' of ABS, DSC, and Brake warning lights appeared. Codes pointed to a pressure sensor failure.

What they tried:

1. Received a $1,200 quote to replace the DSC/ABS module.
2. Removed the electronic portion of the module and mailed it to a rebuild service.

Outcome: The rebuild service cost $200. Reinstalling the repaired original module resolved the lights without requiring dealer programming.

Lesson: For older German vehicles, a rebuild service is a highly cost-effective alternative to full replacement and avoids programming hassles.

How to Prevent This Code From Triggering

• Flush brake fluid every 2-3 years (Every 2-3 years or 30,000 miles) — Brake fluid absorbs moisture, which lowers its boiling point and causes internal corrosion of sensitive ABS module components like solenoid valves.
• Apply dielectric grease to electrical connectors (During any repair involving electrical connections) — Dielectric grease on weather seals keeps moisture and road salt out, preventing pin corrosion that causes high resistance or short circuits.
• Regularly wash the vehicle's undercarriage (Monthly, especially in winter (salt-belt regions)) — Washing away road salt prevents it from accumulating on the ABS module and wheel speed sensor wiring, reducing accelerated corrosion.
• Inspect and secure wiring harnesses (During oil changes or other maintenance) — Ensuring wiring harnesses are properly clipped prevents them from rubbing against suspension components, which wears through insulation and causes shorts.

Frequently Asked Questions

Is it safe to drive with code C1093?

It is not recommended and is extremely risky on certain models. While normal brakes work, disabled anti-lock and stability systems increase the risk of losing control or rollaways. Drive slowly and directly to a repair shop.

How much does it cost to fix code C1093?

Costs vary widely, from $850 to over $1500 for a new ABS module at a shop. Rebuilding your existing module is a cheaper alternative, typically costing $150-$350 plus labor. Simpler fixes like a DSC switch ($90-$250) or wheel hub bearing ($240-$550) cost significantly less.

Can I fix code C1093 myself?

Simple checks like inspecting brake fluid and fuses are DIY-friendly, but replacing the ABS module requires a professional. A new module must be electronically programmed to the car ('Proxy Alignment') and bled using a dealer-level scan tool. Attempting this without the right tools leaves the vehicle unsafe to drive.

What are common misdiagnosis mistakes with C1093?

A major pitfall is replacing the brake light switch on a recalled Jeep/Dodge because the brake lights are stuck on, when the true fault is the ABS module. Another mistake is replacing the ABS module on Mazdas when the actual cause is a cheap DSC OFF switch. Always diagnose the specific suffix code before replacing parts.

I hit a pothole and now my ABS light is on with code C1093. What should I check first?

A sharp impact often damages a wheel speed sensor or its wiring rather than the ABS module itself. A thorough visual inspection of the wheel hub area and sensor connector should be your first step. Use a scan tool to monitor live wheel speed data to pinpoint the damaged sensor.

Will my regular brakes still work with an ABS light on?

Yes, your standard hydraulic brakes will still function normally. The ABS light indicates a failure in the anti-lock assist system, not the primary braking system. However, your wheels will lock up and skid under hard braking, so increase your following distance.

Why did my ABS, traction control, and brake lights all come on at once?

Traction and stability control systems rely entirely on the ABS pump and wheel speed sensors to function. When the ABS module detects a critical fault like C1093, it shuts down all related safety systems as a fail-safe. This triggers all their respective warning lights simultaneously.

What is the difference between C1093-62 and C1093-64?

C1093-62 is a 'Signal Compare Failure' indicating an internal electronic failure within the ABS module itself. C1093-64 is a 'Signal Plausibility Failure' meaning the module receives contradictory data (like deceleration without brake pressure), pointing to air in the lines, fluid issues, or a faulty internal pressure sensor.

What is a 'Proxy Alignment' and is it required?

A Proxy Alignment uses a professional scan tool to introduce a new control module to the vehicle's network and configure it with the car's VIN. It is absolutely required when replacing the ABS module on most modern vehicles, like affected Jeeps and Dodges. Without it, the new module will not function and will trigger a C2206 code.

Can a bad or dead battery cause code C1093?

While low voltage during startup causes random, temporary electronic fault codes, it rarely causes a persistent C1093. This code usually indicates a hard component fault. If multiple unrelated codes appear after a battery issue, clear all codes after fully charging the battery to see if C1093 returns.

Key Takeaways

• Code C1093 disables your vehicle's ABS and traction control systems, requiring immediate diagnosis to restore emergency braking capabilities.
• For 2018-2019 Jeep Grand Cherokee and Dodge Durango models, check your VIN against NHTSA recall #24V838000 to get a failed ABS module replaced for free.
• Always use a professional scanner to read the 2-digit suffix code (like -62 or -64), as this pinpoints whether the failure is an internal module defect or a hydraulic pressure issue.
• Do not replace the brake light switch on a Jeep or Dodge if the brake lights stay on; this is a documented symptom of a C1093-62 internal ABS module failure.
• Before spending $800+ on a new ABS module for a Mazda, test the DSC OFF switch, as a shorted $60 switch frequently triggers this exact code.