Pinpoint Test K : U0121:87
- Refer to Module Communications Network
for schematic and connector information.
Normal Operation and Fault Conditions
The PAM communicates with the ABS module through the HS-CAN.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition PAM U0121:87 Lost Communication With Anti-Lock Brake System (ABS) Control Module "A": Missing Message Sets in continuous memory in the PAM when expected messages from the ABS module are not received for 0.5 second or more. Possible Sources
- Communication concern
- PAM
- ABS module
- K1 VERIFY THE CUSTOMER CONCERN
- Ignition ON.
- Verify there is an observable symptom present.
Is an observable symptom present?
Yes GO to K2 No CLEAR the DTC. The system is operating normally at this time. The DTC may have been set due to high network traffic or an intermittent fault condition. - K2 CHECK THE COMMUNICATION NETWORK
- Using a diagnostic scan tool, perform the network test.
Does the ABS module pass the network test?
Yes GO to K3 No REFER to: Communications Network . - K3 PERFORM THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE SELF-TEST
- Using a diagnostic scan tool, perform the ABS module self-test.
Are any Diagnostic Trouble Codes (DTCs) recorded?
Yes REFER to: Anti-Lock Brake System (ABS) and Stability Control . No GO to K4 - K4 RECHECK THE PAM (PARKING ASSIST CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)
- Using a diagnostic scan tool, clear all Diagnostic Trouble Codes (DTCs).
- Ignition OFF.
- Ignition ON.
- Operate the parking aid system and test for normal operation.
- Check the PAM Continuous Memory Diagnostic Trouble Codes (CMDTCs).
Are any Diagnostic Trouble Codes (DTCs) present?
Yes If DTC U0121:87 is still present, GO to K5 For all other Diagnostic Trouble Codes (DTCs), REFER to PAM DTC Chart . No CLEAR the Diagnostic Trouble Codes (DTCs). The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition. - K5 CHECK FOR DIAGNOSTIC TROUBLE CODE (DTC) U0121:00 OR DIAGNOSTIC TROUBLE CODE (DTC) U0121:87 IN OTHER MODULES
- Using a diagnostic scan tool, clear all Diagnostic Trouble Codes (DTCs).
- Ignition OFF.
- Wait 10 seconds.
- Ignition ON.
- Wait 10 seconds.
- Using a diagnostic scan tool, retrieve the Continuous Memory Diagnostic Trouble Codes (CMDTCs) from all modules.
Is DTC U0121:00 or DTC U0121:87 set in any other module?
Yes GO to K6 No GO to K7 - K6 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION
- Ignition OFF.
- Disconnect and inspect the ABS module connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect the ABS module connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, Refer to ABS Guided Routine Testing . No The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues. - K7 CHECK FOR CORRECT PAM (PARKING ASSIST CONTROL MODULE) OPERATION
- Ignition OFF.
- Disconnect and inspect the PAM connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect the PAM connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new PAM. REFER to: Parking Assist Control Module (PAM) . No The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.