Pinpoint Test I : U0121:00

WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

I1 VERIFY THE CUSTOMER CONCERN

Ignition ON.

Verify there is an observable symptom present.

Is an observable symptom present?

Yes

GO to I2

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.

I2 CHECK THE COMMUNICATION NETWORK
- Using a diagnostic scan tool, perform a network test.
Does the ABS module pass the network test?

Yes GO to I3

No REFER to Communications Network

I3 RETRIEVE THE RECORDED DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE CCM (CRUISE CONTROL MODULE), ABS (ANTI-LOCK BRAKE SYSTEM) MODULE AND PCM (POWERTRAIN CONTROL MODULE) SELF-TESTS

Using a diagnostic scan tool, perform a CCM self-test.

Using a diagnostic scan tool, perform a ABS module self-test

Using a diagnostic scan tool, perform a PCM self-test

Are any low or high voltage Diagnostic Trouble Codes (DTCs) recorded?

Yes

If DTC U3003:16 is recorded in the CCM, GO to Pinpoint Test Q If DTC U3003:17 is recorded in the CCM, GO to Pinpoint Test R If Diagnostic Trouble Codes (DTCs) were recorded in the PCM, Refer to the appropriate Engine article for the procedure. If Diagnostic Trouble Codes (DTCs) were recorded in the ABS module, REFER to: Anti-Lock Brake System (ABS) and Stability Control .

GO to I4

I4 CHECK THE GWM (GATEWAY MODULE A) DIAGNOSTIC TROUBLE CODES (DTCS)
- Using a diagnostic scan tool, retrieve the GWM Continuous Memory Diagnostic Trouble Codes (CMDTCs).
Are any Diagnostic Trouble Codes (DTCs) recorded?

Yes REFER to Communications Network

No GO to I5

I5 RECHECK THE CCM (CRUISE CONTROL MODULE) AND PCM (POWERTRAIN CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

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 performed.

Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs). Repeat the CCM and PCM self-tests.

Is CCM DTC U0121:00 or PCM DTC U0121 still present?

Yes

GO to I6

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.

I6 CHECK FOR DTC (DIAGNOSTIC TROUBLE CODE) U0121:00 OR U0121
- Using a diagnostic scan tool, clear all Diagnostic Trouble Codes (DTCs).
- Ignition OFF.
- Ignition ON.
- Wait 10 seconds.
- Using a diagnostic scan tool, perform a self-test.
- Retrieve the Continuous Memory Diagnostic Trouble Codes (CMDTCs) from all modules.
Does DTC U0121:00 or U0121 set in other modules?

Yes INSTALL a new ABS module. REFER to: Anti-Lock Brake System (ABS) Module .

No If the CCM sets DTC U0121:00, INSTALL a new CCM. REFER to: Cruise Control Module (CCM) . If the PCM sets U0121, GO to I7

I7 CHECK FOR CORRECT PCM (POWERTRAIN CONTROL MODULE) OPERATION

Ignition OFF.

Disconnect and inspect all PCM 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 PCM 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 service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, Refer to PCM Guided Routine Testing .

No	The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.