U0418 on 2019-2021 Jeep Cherokee: Brake System Data Error Causes & Fixes

What's Unique About the 2019-2021 Jeep CHEROKEE

For the 2019-2021 Jeep Cherokee, this code has a well-documented and specific sensitivity to low battery voltage. Multiple Technical Service Bulletins (TSBs) issued by FCA (now Stellantis) explicitly state that U0418 can be set erroneously simply because the battery voltage has dropped below 10 volts. This makes checking the battery health the absolute first step, as it's a known platform-specific quirk that can save significant diagnostic time and money. The vehicle's Engine Stop-Start (ESS) system places high demands on the battery, making it more susceptible to voltage drops that can trigger this code.

Diagnostic Flowchart

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

Symptoms You May Notice

• Malfunction Indicator Lamp (MIL) or Check Engine Light is on.
• ABS warning light is on.
• Traction Control or Electronic Stability Control (ESC) light is on.
• "Service 4WD System" message may ap 🎬 Watch: Diagnosing a Service 4WD light on a Jeep Cherokeepear.
• Cruise control may become unavailable or disengage unexpectedly.
• "Stop/Start Unavailable" message may appear.
• In some cases, the alarm system may act erratically.

Most Likely Causes

1. Low Battery Voltage / Weak or Failing Battery 🔴 High Probability Multiple manufacturer TSBs confirm that a battery voltage below 10 volts can erroneously trigger code U0418 on this platform. The Engine Stop-Start (ESS) system puts a heavy load on the battery, potentially shortening its lifespan and causing voltage drops that lead to this code.
   How to confirm: Use a multimeter to check the battery voltage with the engine off (should be ~12.4-12.6V). Perform a load test on the battery at an auto parts store or repair shop to check its health. Check the Intelligent Battery Sensor (IBS) connector on the negative terminal for a secure connection.
   Typical fix: Replace the vehicle's 12V battery. The common size is a Group H7 (also called 94R) AGM battery. After replacement, ensure the IBS is reconnected properly.
   Est. part cost: $200-$450
2. Corrupted PCM Software 🟡 Medium Probability TSBs have been issued to update the Powertrain Control Module (PCM) software to correct issues that can lead to this code. TSB 18-078-22 applies to the 2.4L engine, while 18-047-20 applies to the 3.2L V6.
   How to confirm: A dealership or qualified shop with a wiTECH scan tool can check the current software calibration ID of the PCM against the latest available version referenced in the TSBs.
   Typical fix: Reprogram the PCM with the latest manufacturer software. This is typically a dealer-only or specialized shop repair and may be covered under warranty.
   Est. part cost: $0-$200
3. Damaged or Corroded Wiring/Connectors ⚪ Low Probability Wiring to wheel speed sensors or the main ABS module harness can get damaged from road debris, improper repairs, or corrosion. On related Jeep platforms, owners have found wires rubbed through near the rear differential or at the wheel speed sensor connectors after off-roading.
   How to confirm: Visually inspect the wiring harnesses leading to the ABS module and each wheel speed sensor for breaks, chafing, or corrosion. Pay close attention to the harness routing and any points where it might contact sharp edges on the chassis or suspension components.
   Typical fix: Repair the damaged section of the wiring harness or clean/replace the affected connector. Use dielectric grease on connectors to prevent future moisture intrusion.
   Est. part cost: $10-$150
4. Failing Brake System Control Module (ABS Module) ⚪ Low Probability
   How to confirm: This is typically a last resort after all other causes (battery, software, wiring) have been ruled out. Diagnosis requires an advanced scan tool to attempt direct communication with the module and verify its internal status. If the module is unresponsive and has proper power and ground, it is likely faulty.
   Typical fix: Replace the ABS module. This part requires a "PROXI Alignment" procedure with a compatible scan tool to program it to the vehicle's VIN and configuration. Failure to do so will result in a flashing odometer and other errors.
   Est. part cost: $500-$1200

Rare But Worth Checking

• Faulty Wheel Speed Sensor:

Diagnosis Steps

1. Check for other DTCs. Additional codes, especially for wheel speed sensors (U140x), provide critical clues.
2. Install a battery charger or use a multimeter to verify battery voltage is stable and above 12.4V. A professional load test is highly recommended to confirm the battery's health, even if voltage seems okay.
3. Inspect battery terminals and the Intelligent Battery Sensor (IBS) on the negative terminal for tightness and corrosion. Clean as necessary.
4. If battery and connections are good, clear the codes and perform a test drive. If the code does not return, it was likely a transient low-voltage event.
5. If the code returns, check with a dealer if TSB #18-078-22 (for 2.4L) or #18-047-20 (for 3.2L) software updates are applicable and have been performed on your vehicle.
6. Perform a thorough visual inspection of the wiring harness to the ABS control module and all four wheel speed sensors. Look for any signs of damage, chafing, or corrosion, especially where the harness passes near moving parts or sharp edges.
7. Using an advanced scan tool, monitor live data from the Brake System Control Module. Check for erratic readings from wheel speed sensors while driving.
8. If wiring is intact and software is up-to-date, and the battery is confirmed good, the final step is to suspect a faulty ABS control module. Before replacement, verify power and ground at the module connector.
🎬 Watch: A pro mechanic's guide to ABS diagnosis and repair
9. If replacing the ABS module, a PROXI alignment procedure must be performed to sync the new module with the vehicle.

Parts You'll Likely Need

• 12V AGM Battery (OEM #Commonly Group Size H7 / 94R) — This is the most common cause for this specific code on this vehicle, as documented by multiple manufacturer TSBs and countless owner experiences.
  Trusted brands: Mopar, Interstate, Duralast, DieHard
  OEM price range: $250-$400
  Aftermarket price range: $200-$350
• Brake System Control Module (ABS Module) (OEM #Varies by option, e.g., 68496426AA (w/o adaptive cruise), 68373859AC (w/ adaptive cruise). Always verify with VIN.) — If the battery, wiring, and software are confirmed to be good, the module that originates the signal is the next logical point of failure.
  Trusted brands: Mopar
  OEM price range: $600-$900
  Aftermarket price range: $400-$800 (rebuilt)

Related Codes That Often Appear With This One

• P1D83 — Mentioned in TSB #1812022 as appearing with U0418, often related to low voltage events.
• P0031 — Mentioned in TSB #18-078-22 as appearing with U0418 on 2.4L models, addressed by a PCM software update.
• U0151 — Listed alongside U0418 in TSBs #1807722 and #18-023-19 REV. B, indicating a broader communication network issue.
• U0102 — Lost communication with transfer case module. Can appear with U0418 if a wiring short affects multiple systems, as seen in a Jeep Gladiator repair where a diff locker wire shorted out.
• U1409 / U140A — These are codes for implausible wheel speed sensor signals. A fault in a wheel speed sensor circuit is a primary reason for the ABS module to send invalid data, directly causing U0418.

Technical Service Bulletins (TSBs) & Recalls

• 1812022: Notes that U0418 can be set erroneously due to a low battery (below 10 volts).
• 1807722: Lists U0418 as part of a group of potential communication DTCs.
• 18-078-22: For 2.4L engines, states U0418 can be set due to a low battery and provides a PCM software update as a fix.
• 18-023-19 REV. B: Superseded by 18-047-20, lists U0418 as part of a group of potential communication DTCs.
• 1807822: Confirms MIL illumination for U0418 and points to low battery voltage as a potential erroneous cause.
• 18-047-20: For 3.2L V6 engines, involves reprogramming the PCM to fix a list of DTCs including U0418.

Platform-Specific Known Issues

• This vehicle platform is highly sensitive to low battery voltage, which can cause the U0418 code to set without any actual fault in the brake system. This is explicitly noted in TSBs like 18-078-22, which states the code can be set erroneously below 10 volts.
• Software glitches in the Powertrain Control Module (PCM) can also cause this code. TSB #18-078-22 (for 2.4L engines) and TSB #18-047-20 (for 3.2L engines) involve reprogramming the PCM to resolve the issue.
• Replacement of the ABS Control Module is not a plug-and-play repair. It requires a mandatory 'PROXI Alignment' procedure using a dealer-level scan tool to synchronize the new module with the vehicle's other computers.

Mechanic-Grade Diagnostic Values

• Wheel Speed Sensor Resistance (Ohms) — expected: No single specification is provided; the value should be nearly identical to the sensor on the opposite side of the same axle (e.g., compare front left to front right).. Failure: A reading of 'OL' (Open Loop/open circuit) or a resistance value that is significantly different from the known-good sensor on the other side indicates a faulty sensor or wiring.

Scan Tool Commands That Help

• wiTECH (or compatible advanced aftermarket tool like Appcar DiagFCA): Proxi Configuration Alignment — This procedure is mandatory after replacing the ABS control module. It synchronizes the vehicle's configuration map from the Body Control Module (BCM) to all other modules on the network. Failure to perform this alignment will result in a flashing odometer, persistent warning lights, and communication DTCs, as the vehicle will not recognize the new module.

OEM Part Supersession History

• 68472374AA, 68472374AB → 68496426AA — Standard part revision and update by the manufacturer.
  Heads up: This applies to the ABS module for vehicles without Adaptive Cruise Control. Always verify the correct part number with the vehicle's VIN.