PINPOINT TEST H : U0121:00 or U0129
- H1 VERIFY THE CUSTOMER CONCERN
- Ignition ON.
- Verify there is an observable symptom present.
Is an observable symptom present?
Yes GO to H2. 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. - H2 CHECK THE COMMUNICATION NETWORK
- Ignition ON.
- Using a scan tool, perform a network test.
Does the ABS module pass the network test?
Yes GO to H3. No Refer to article 'Module Communications Network', Go to Pinpoint Test B . - H3 RETRIEVE THE RECORDED DTCs FROM THE C-CM, ABS MODULE AND PCM SELF-TESTS
- Using a scan tool, perform the self-test on the following modules.
- C-CM
- ABS module
- PCM
Are any low or high voltage DTCs recorded?
Yes For the C-CM, GO to Pinpoint Test Q or GO to Pinpoint Test R . For ABS module, Refer to article 'Anti-Lock Brake System (ABS) and Stability Control', Go to Pinpoint Test A or Refer to article 'Anti-Lock Brake System (ABS) and Stability Control', Go to Pinpoint Test P . For PCM, Refer to article 'Charging System', Go to Pinpoint Test B (Diagnostic Trouble Code (DTC) P0562), or Refer to article 'Charging System', Go to Pinpoint Test A (Diagnostic Trouble Code (DTC) P0563). No GO to H4. - Using a scan tool, perform the self-test on the following modules.
- H4 RECHECK THE C-CM DTCs
- Using a scan tool, clear the DTCs.
- Repeat the C-CM self-test.
Is DTC U0121:00 still present?
Yes GO to H5. 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. - H5 CHECK FOR DTC U0121:00 OR DTC U0129 SET IN OTHER MODULES
- Using a scan tool, clear all DTCs.
- Ignition OFF.
- Wait 10 seconds.
- Ignition ON.
- Using a scan tool, perform Self-Test.
- Retrieve the continuous memory DTCs from all modules.
Do both the C-CM set DTC U0121:00 and the PCM set DTC U0129?
Yes INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) and Stability Control . No INSTALL a new C-CM. Refer to Cruise-Control Module (C-CM) .