Pinpoint Test N : U0121:00

N1 VERIFY THE CUSTOMER CONCERN

Ignition ON.

Verify there is an observable symptom present.

Is an observable symptom present?

Yes	GO to N2.
No	The system is operating normally at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

N2 CHECK THE COMMUNICATION NETWORK

Using a scan tool, perform network test.

Does the ABS module pass the network test?

Yes	GO to N3.
No	Refer to article 'Module Communications Network', Go to Pinpoint Test B .

N3 RETRIEVE THE RECORDED DTCs FROM THE BCM SELF-TEST

Using a scan tool, perform BCM self-test.

Check for recorded BCM DTCs from the self-test.

Is DTC U3003:16 or DTC U3003:17 recorded?

Yes	For DTC U3003:16, GO to Pinpoint Test H . For DTC U3003:17, GO to Pinpoint Test I .
No	GO to N4.

N4 CHECK FOR DTCs U3003:16 AND U3003:17 FROM THE ABS MODULE SELF-TEST

Using a scan tool, retrieve the continuous memory DTCs from the ABS module.

Is DTC U3003:16 or DTC U3003:17 recorded?

Yes	For DTC U3003:16, Refer to article 'Anti-Lock Brake System (ABS) and Stability Control', Go to Pinpoint Test A . For DTC U3003:17, Refer to article 'Anti-Lock Brake System (ABS) and Stability Control', Go to Pinpoint Test P .
No	GO to N5.

N5 RECHECK THE BCM DTCs

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

Using a scan tool, clear the DTCs. Repeat the BCM self-test.

Is DTC U0121:00 still present?

Yes	GO to N6.
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.

N6 CHECK FOR DTC U0121:00 SET IN OTHER MODULES

Clear the DTCs.

Ignition OFF.

Ignition ON.

Wait 10 seconds.

Using a scan tool, retrieve the continuous memory DTCs from all modules.

Is DTC U0121:00 set in any other module?

Yes	INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) and Stability Control . CLEAR the DTCs.
No	INSTALL a new BCM. REFER to Body Control Module (BCM) - With Intelligent Access (IA) or REFER to Body Control Module (BCM) - Without Intelligent Access (IA) .