Pinpoint Test G : DTC (Diagnostic Trouble Code) U0121:87

G1 VERIFY THE CUSTOMER CONCERN

Ignition ON.

Verify there is an observable symptom present.

Is there an observable symptom present?

Yes

GO to G2

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.

G2 CHECK THE COMMUNICATION NETWORK

Using a diagnostic scan tool, perform a network test.

Does the ABS module pass the network test?

Yes

GO to G3

No	See the Symptom Chart: Communication Network, the ABS module does not respond to the diagnostic scan tool. REFER to: Module Communications Network (Hybrid/Energi) .

G3 PERFORM THE IPMA (IMAGE PROCESSING MODULE A) SELF-TEST
- Using a diagnostic scan tool, perform the IPMA self-test.
Are any non-network Diagnostic Trouble Codes (DTCs) present?

Yes DIAGNOSE all non-network Diagnostic Trouble Codes (DTCs). REFER to IPMA DTC Chart.

No GO to G4

G4 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	DIAGNOSE all non-network Diagnostic Trouble Codes (DTCs). REFER to:Anti-Lock Brake System (ABS) And Stability Control (Hybrid/Energi) .

GO to G5

G5 RECHECK THE IPMA (IMAGE PROCESSING MODULE A) DIAGNOSTIC TROUBLE CODES (DTCS)

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

Ignition OFF.

Ignition ON.

Wait 10 seconds.

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

Check the IPMA Diagnostic Trouble Codes (DTCs).

Is DTC U0121:87 still present?

Yes

GO to G6

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.

G6 CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN

NOTE: If new modules were installed prior to the DTC being set, the module configuration may 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 IPMA. 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

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

Is the observable symptom still present?

Yes

GO to G7

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

G7 CHECK FOR CORRECT ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OPERATION

Ignition OFF.

Disconnect and inspect the ABS module connectors and related in-line connectors.

Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

Reconnect the ABS module connectors 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 Technical Service Bulletins (TSBs) address this concern, Refer to Anti-Lock Brake System Component Testing (Hybrid/Energi) .

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.