U0420 on 2019 Lincoln MKC: Causes for Invalid Power Steering Data & Fixes

What's Unique About the 2019-2019 Lincoln MKC

This specific issue on the 2019 MKC is so well-known that Lincoln released a series of Technical Service Bulletins (TSBs) about it. The problem primarily affects models without lane keep assist and is often triggered by a momentary low voltage during engine start. Over time, Lincoln's recommended fix evolved from a simple software update to a complete replacement of the ABS module with an improved part, indicating a hardware-level sensitivity in the original module that was later corrected.

Diagnostic Flowchart

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

Symptoms You May Notice

• "AdvanceTrac" warning message on the dashboard
• "Hill Start Assist Not Available" message
• Illuminated Electronic Stability Control (ESC) or Traction Control warning lamp
• "Service AdvanceTrac" me 🎬 Watch: See these specific warning lights and messages in action.ssage

Most Likely Causes

1. Defective ABS Control Module 🔴 High Probability Per Lincoln's final Technical Service Bulletin (SSM 51099), the original ABS module is overly sensitive to low voltage events during startup, causing it to set communication faults. An updated part is required for a permanent fix. This bulletin supersedes all previous advice.
   How to confirm: Confirm with a professional scan tool that U0420 is in the ABS module and U0415 is in the PSCM. If previous software updates (per TSB SSM 48083) did not resolve the issue, or if the vehicle is a 2019 MKC without lane keep assist, module replacement is the next step per the latest TSB.
   Typical fix: Replace the ABS control module with the updated part number KJ7Z-2C219-C. The new module will require programming (PMI) to the vehicle using a dealer-level scan tool.
   Est. part cost: $400-$550
2. ABS Module Software Issue 🟡 Medium Probability An earlier fix recommended by Lincoln (TSB SSM 48083) was to reprogram the ABS module. This may resolve the issue on some vehicles but was later superseded by the recommendation to replace the module entirely, suggesting the software patch was not a complete solution for the underlying hardware sensitivity.
   How to confirm: A dealer or qualified shop can check the current software calibration of the ABS module and see if an update is available per TSB SSM 48083. If the update has been done and the problem persists, the module is faulty.
   Typical fix: Reprogram the ABS control module with the latest software level using a Ford/Lincoln diagnostic scan tool. This is now considered an interim step before full replacement.
   Est. part cost: $0
3. Weak Battery or Low Voltage Event ⚪ Low Probability The TSBs state these codes can be inadvertently set by low system voltage during a vehicle start. While a weak battery can be the trigger, it often exposes the underlying sensitivity of the original ABS module rather than being the sole cause. A healthy vehicle should not set these codes from a normal start. Also note, a major recall (NHTSA 23V378000) exists for a battery monitor sensor fire risk on all 2015-2019 MKCs, highlighting potential electrical issues in this area.
   How to confirm: Test the battery's health, including its voltage during cranking. A healthy battery should maintain voltage above ~10.5V during a start. Ensure the battery monitor sensor recall has been performed.
   Typical fix: Charge or replace the vehicle's 12V battery and clear the codes. If the codes return, the issue is with the module, not the battery.
   Est. part cost: $150-$300

Rare But Worth Checking

• Wiring Harness Issue: While the TSBs point to a module issue, it's always possible for a communication code to be caused by a damaged wire or corroded connector in the CAN bus harness between the ABS module and the PSCM. This should be investigated if a new module does not fix the issue. A Reddit user with similar codes on a Ford Explorer found their issue was caused by a bad wire or connector.

Diagnosis Steps

1. Check and charge the battery to ensure it is in good health. Clear all codes and restart the vehicle to see if the codes immediately return.
2. Using a professional scan tool (like Ford IDS or FORScan), pull codes from ALL vehicle modules.
3. Confirm that DTC U0420 is present in the ABS module and DTC U0415 is present in the PSCM.
4. Check vehicle history to see if it is a 2019 MKC without lane keep assist, as this is the model specified in the TSBs.
5. Consult Lincoln's TSBs. First, check if the ABS module software is up to date (per TSB SSM 48083).
6. If the software is current or the update does not fix the issue, proceed with the fix outlined in the most recent TSB, SSM 51099, which is to replace the ABS control module.
7. After replacement, the new module must be programmed to the vehicle using a PMI procedure with a compatible scan tool.
8. If problems persist, perform a detailed inspection of the CAN bus wiring and connectors between the ABS and PSCM modules for damage or corrosion.

Parts You'll Likely Need

• ABS Control Module (OEM #KJ7Z-2C219-C) — This is the updated part specified by Lincoln in TSB SSM 51099 to permanently resolve the communication fault. It supersedes part number KJ7Z-2C219-B.
  Trusted brands: Motorcraft
  OEM price range: $400 - $560
  Aftermarket price range: N/A

Related Codes That Often Appear With This One

• U0415 — This code, 'Invalid Data Received From ABS Module', is set in the Power Steering Control Module (PSCM) at the same time U0420 is set in the ABS module. They indicate a mutual communication breakdown and are almost always found together for this specific fault, as documented in multiple TSBs.

Technical Service Bulletins (TSBs) & Recalls

• SSM 51099: Recommends replacing the ABS control module with part KJ7Z-2C219-C.
• SSM 48506: Describes the issue with DTCs U0420 and U0415 on 2019 MKC without lane keep assist.
• SSM 48083: Recommends reprogramming the ABS control module as a potential fix.
• SSM 47910: Initial bulletin, advises charging battery and clearing codes, acknowledging an investigation.

Platform-Specific Known Issues

• TSB SSM 51099 states that for 2019 MKC vehicles without lane keep assist exhibiting codes U0420 and U0415, the definitive fix is to replace the ABS control module with part number KJ7Z-2C219-C.
• An earlier TSB, SSM 48083, suggested that reprogramming the ABS control module could resolve the concern, which may have been a temporary or less effective solution before the hardware revision was released.
• The initial TSB, SSM 47910, simply advised charging the battery and clearing codes, noting that engineering was investigating a permanent fix. This bulletin shows the first acknowledgement of the problem.
• A major recall for underhood fire risk (NHTSA Campaign 23V378000) affects all 2015-2019 Lincoln MKCs due to a potentially shorting battery monitor sensor. While not directly causing U0420, it highlights the sensitivity of the vehicle's electrical system near the battery.

Mechanic-Grade Diagnostic Values

• HS-CAN Bus Network Resistance — expected: ~60 Ohms. Failure: A reading of ~120 Ohms indicates an open circuit or one of the two terminating resistors is offline. A reading significantly different from 60 Ohms can indicate a wiring short.
• HS-CAN High Voltage (Key On, Engine Off) — expected: ~2.6 Volts (average). Failure: Voltage at 0V may indicate a short to ground. Voltage significantly higher or lower suggests a network fault.
• HS-CAN Low Voltage (Key On, Engine Off) — expected: ~2.4 Volts (average). Failure: Voltage at 0V may indicate a short to ground. Voltage significantly higher or lower suggests a network fault.
• ABS Module Ground Resistance — expected: < 5 Ohms (ideally < 0.1 Ohms). Failure: High resistance indicates a poor ground connection at point GD121, which can cause intermittent module behavior.

Hidden / Shadow Codes Worth Checking

• U0420-86: This is a more specific version of U0420. The '-86' suffix is a Failure Type code meaning 'Signal Invalid'. It indicates that the ABS module is receiving data from the PSCM, but the data is not plausible or is outside the expected range for the current operating conditions. This confirms it's a data integrity problem, not a complete loss of communication. (see via This sub-code is visible with dealer-level scan tools like Ford IDS or advanced aftermarket tools like FORScan.)

Scan Tool Commands That Help

• Ford IDS / FORScan: Programmable Module Installation (PMI) — This function is mandatory after replacing the ABS control module. It copies the vehicle's configuration data (As-Built data) from the old module and writes it to the new one. If the old module is unresponsive, this data must be downloaded from Ford's service portal and entered manually.
• Professional Scan Tool: ABS Service Bleed — After the physical replacement of the ABS module and hydraulic unit, air is introduced into the brake system. This command cycles the ABS pump and valves to purge trapped air from the hydraulic block, which cannot be done with a manual brake bleed alone.
• Ford IDS / FORScan: Module Self-Test — Before replacing parts, running a self-test on the ABS and PSCM modules can help verify if the modules themselves report any internal errors, which can help confirm a module is faulty.

Wiring & Ground Locations

• ABS Control Module — Located in the engine bay, behind the battery and tucked between the brake booster and the driver's side strut tower.. This is the physical location of the module that sets code U0420 and requires replacement per the TSB.
• C135 — This is the main electrical connector for the ABS control module.. Technicians must test for power, ground, and CAN bus signals at this connector to rule out wiring issues before condemning the module. Pins can be checked for corrosion or damage.
• GD121 — This is the designator for the ABS module's ground point, described as 'GROUND - FENDER. FRONT LEFT # 2ND POINT'. It is connected via a Black/Yellow wire to Pins 13 and 38 of the C135 connector.. A loose or corroded ground at this specific point can cause a variety of communication and module errors, including U0420. It is a critical point to inspect and clean during diagnosis.
• HS-CAN 2 Bus at C135 — Pin 26 (CAN High, Green/Orange wire) and Pin 14 (CAN Low, Gray/Blue wire) on the ABS module connector.. These are the specific pins where a technician can measure the CAN bus resistance (~60 Ohms) and voltage (~2.4V/2.6V) to verify the health of the communication network directly at the module.

Real Owner Repair Stories

• YouTube channel 'Watch Wes Work' (2015-2020 Ford F-150 (different vehicle, but same companion code U0415 and similar system logic)) — Service AdvanceTrac warning, ABS light, and Hill Descent Control Fault messages.
  ❌ Tried (didn't work) Initial diagnosis pointed towards a faulty ABS control module.
  ✅ What actually fixed it A visual inspection revealed that the wiring harness for the front left wheel speed sensor had been rubbed through by the tire, exposing the copper wires. The final fix was to replace the entire ABS wheel speed sensor and its integrated wiring harness.

"I Checked Everything" — The Actual Cause

• While not a smoke test, a similar pattern exists for this code where all modules may appear to communicate intermittently, but the fault persists. In one documented case on a related Ford platform, the initial diagnosis pointed to a faulty ABS module, but the actual root cause was a simple chafed wire on a wheel speed sensor harness. This highlights the importance of physically inspecting all related wiring for damage before replacing expensive control modules.

OEM Part Supersession History

• KJ7Z-2C219-B → KJ7Z-2C219-C — Part revision to address the hardware sensitivity issue described in TSB SSM 51099. The 'C' version is the corrected part.
  Heads up: Using the older '-B' part, even if new, will likely result in the same fault returning. Only the '-C' version should be used for this repair.