LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Audi >> 2017 >> S8 >> Repair and Diagnosis >> External Pages >> Different car >> Section 1301 (Abs Guided Routine Testing) >> Pinpoint Tests >> Pinpoint Test BT: DTC P1637: PCM ABS Module CAN Link Error >> Possible Causes
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Possible Causes

WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.
  1. BT1: CHECK THE ABS MODULE COMMUNICATION 
    • Ignition ON, engine OFF.
    • Press the Read Vehicle Information button to view the results of the modules communicating on the network.
    • Retrieve the continuous memory DTCs.
    • Does the ABS module pass the Network Test? 
    Yes No
    Go to  BT2. DIAGNOSE the scan tool does not communicate with the ABS module. REFER to MODULE COMMUNICATIONS NETWORK (2 OF 2) .
  2. BT2: CHECK THE GWM COMMUNICATION 
    • Review the results of the modules communicating on the network from the previous step.
    • Did the GWM pass the Network Test? 
    Yes No
    Go to  BT3. DIAGNOSE the scan tool does not communicate with the GWM. REFER to MODULE COMMUNICATIONS NETWORK (2 OF 2) .
  3. BT3: CHECK FOR ABS MODULE DTCS 
    • Carry out the ABS self-test.
    • Are any DTCs present? 
    Yes No
    DIAGNOSE the ABS module DTC. REFER to the ABS Module DTC Chart. Go to  BT4.
  4. BT4: CHECK FOR GWM DTCS 
    • Carry out the GWM self-test.
    • Are any DTCs present? 
    Yes No
    DIAGNOSE the GWM DTC. REFER to MODULE COMMUNICATIONS NETWORK (2 OF 2) . Go to  BT5.
  5. BT5: CHECK FOR PCM DTCS 
    • Carry out the PCM KOEO self-test.
    • Are any DTCs present? 
    Yes No
    DIAGNOSE the PCM DTC. REFER to the ELECTRONIC ENGINE CONTROLS - 3.5L ECOBOOST (272KW/370PS) . Go to  BT6.
  6. BT6: RECHECK FOR PCM DTCS 
    • Clear the PCM DTCs.
    • Ignition OFF.
    • Ignition ON, engine OFF.
    • Carry out the PCM KOEO self-test.
    • Are any DTCs present? 
    Yes No
    DIAGNOSE the PCM DTC. REFER to the ELECTRONIC ENGINE CONTROLS - 3.5L ECOBOOST (272KW/370PS) . Go to  BT7.
  7. BT7: CHECK THE TRACTION CONTROL SYSTEM 
    • Test drive the vehicle.
      • Carry out at least 1 ABS loose gravel acceleration and stop.
    • Ignition OFF.
    • Ignition ON, engine OFF.
    • Carry out the PCM KOEO self-test.
    • Are any DTCs present? 
    Yes No
    For KOEO DTC P1637,
    SET the ignition to OFF. DISCONNECT all PCM and ABS module electrical connectors.
    INSPECT the connectors for signs of corrosion, bent pins, pushed-out pins and spread terminals. REPAIR as necessary.
    For all others,
    DIAGNOSE the PCM DTC. REFER to the ELECTRONIC ENGINE CONTROLS - 3.5L ECOBOOST (272KW/370PS) .    		 The system is operating correctly at this time. The concern may be caused by a loose or corroded connector.
scientia non olet · About LEMON Manuals