Pinpoint Test L: U0121:00

WARNING: This page is about a different car, the 2020 Lincoln Nautilus. However, it is still accessible from the selected car via links, so may be relevant.

L1 VERIFY THE CUSTOMER CONCERN

Verify there is an observable symptom present.

Is an observable symptom present?

Yes

GO to L2

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.

L2 CHECK THE COMMUNICATION NETWORK
- Using a diagnostic scan tool, perform the network test.
Does the ABS module pass the network test?

Yes GO to L3

No REFER to: Communications Network .

L3 PERFORM THE PAM (PARKING ASSIST CONTROL MODULE) CONTROL MODULE SELF-TEST
- Using a diagnostic scan tool, perform the PAM module self-test.
Are any non-network Diagnostic Trouble Codes (DTCs) present?

Yes REFER to DTC Chart: Parking Aid Module (PAM) .

No GO to L4

L4 CHECK THE GWM (GATEWAY MODULE A) DIAGNOSTIC TROUBLE CODES (DTCS)
- Using a diagnostic scan tool, check the GWM Continuous Memory Diagnostic Trouble Codes (CMDTCs).
Are any Diagnostic Trouble Codes (DTCs) recorded?

Yes REFER to: Communications Network .

No GO to L5

L5 PERFORM THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE SELF-TEST
- Using a diagnostic scan tool, perform the ABS module self-test.
Are any non-network Diagnostic Trouble Codes (DTCs) present?

Yes REFER to: Anti-Lock Brake System (ABS) and Stability Control .

No GO to L6

L6 RECHECK THE PAM (PARKING ASSIST CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

Using a diagnostic scan tool, clear the PAM Diagnostic Trouble Codes (DTCs).

Ignition OFF.

Ignition ON.

Wait 10 seconds.

Using a diagnostic scan tool, perform the PAM continuous memory self-test.

Check the PAM Continuous Memory Diagnostic Trouble Codes (CMDTCs).

Is DTC U0121:00 present?

Yes

GO to L7

No	The system is operating correctly at this time. The DTC may have been set due to high network traffic, or an intermittent fault condition.

L7 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN

NOTE: If new modules were installed prior to the DTC being set, the module configuration can be incorrectly set during the PMI, or the PMI may not have been carried out.

CHECK the vehicle service history for recent service actions related to the ABS module or PAM. If recent service history is found:
- verify correct replacement module was installed
  - HVBOM may be used to verify correct part fitment
- verify the configuration of replacement module was correct
  - re-configure module using as-built data if prior configuration is suspect
- verify the module was not obtained from a like vehicle and installed into customer vehicle
  - return the swapped module to source vehicle and obtain new replacement module
  - if a new replacement module is installed, PERFORM PMI using as-built data

Operate the system and determine if the observable symptom is still present.

Is the observable symptom still present?

Yes

GO to L8

No	The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.

L8 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION

Ignition OFF.

Disconnect and inspect all ABS module and related in-line 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 and related in-line 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 the TSB instructions. If no TSB addresses this concern, INSTALL a new ABS module. REFER to: Anti-Lock Brake System (ABS) Module .

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.