B1A28-ECM MISMATCH WITH SKIM

For a complete wiring diagram, refer to the Wiring Information.

When Monitored:
At ignition on, after ignition on during any rolling code handshake that occurs with the PCM due to a SKIM or PCM reset.
Set Condition:
When a PCM/ECM STATUS message with a Valid Key status is not received by the Wireless Control Module (WCM) within 3.5 seconds of transmitting the last Valid Key Code message to the PCM/ECM.

Possible Causes
VERIFYING PCM VIN
INTERMITTENT WIRING HARNESS PROBLEM
POWERTRAIN CONTROL MODULE (PCM)

1. DETERMINING IF DIAGNOSTIC TROUBLE CODE (DTC) IS CURRENT

NOTE: An external Radio-Frequency Identification (RFID) key (and/or pass/radio key), such as one used to gain access to a 24 hour gym, can cause this DTC to set and create a no start condition. Inspect the customer's key chain for any type of RFID key. If one is not found, question the customer to see if a spare key chain has this RFID key on it or if it was removed from the original key chain before the vehicle was released for service. If a RFID key is present, remove the ignition key from the vehicle and remove the RFID key from the key chain. For GPEC equipped vehicles, disconnect the battery and wait a minimum of 5 minutes, reconnect and attempt to start the vehicle. For NGC equipped vehicles, turn the ignition on a minimum for one hour, and then attempt to start the vehicle. If the vehicle does not start, continue with the diagnostic test.

1.	With the scan tool, erase the WCM DTCs.

2.	Turn the ignition off.

3.	Wait 10 seconds.

4.	Turn the ignition on and wait two minutes.

5.	With the scan tool, read the WCM DTCs.

Does the scan tool display the DTC that was previously erased?

Yes

Go To 2

Go To 4

2. VERIFYING THE PCM VIN

1.	Turn the ignition on.

2.	With the scan tool, select Engine system from the main menu.

3.	Display and record the Vehicle Identification Number.

NOTE: Make sure that a VIN has been programmed into the PCM. If a VIN is not displayed, attempt to program the PCM with the correct VIN before continuing.

Does the VIN recorded from the PCM match the VIN of the vehicle?

Yes

Go To 3

Using the scan tool perform the PCM Replace procedure to update the VIN in the PCM.
Perform the WCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Wireless Control (WCM) - Standard Procedure).

3. REPLACE WCM AND CHECK DTCS

1.	Turn the ignition off.

2.	Replace and program the Wireless Control Module in accordance with the Service Information.

3.	Turn the ignition on.

4.	With the scan tool, display and clear all PCM and WCM DTCs.

5.	Perform five ignition key cycles leaving the ignition key on for 90 seconds per cycle.

6.	With the scan tool, check for WCM DTCs.

Does the scan tool display the same DTC?

Yes

Replace and program the Powertrain Control Module in accordance with the Service Information.
Perform the WCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Wireless Control (WCM) - Standard Procedure).

The repair is complete.
Perform the WCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Wireless Control (WCM) - Standard Procedure).

4. INTERMITTENT

1.	Turn the ignition off.

NOTE: Check for the following conditions:

Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.

Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.

Perform any Technical Service Bulletins (TSB) that may apply.

Were any problems found?

Yes

Repair wiring harness/connectors as necessary.
Perform the WCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Wireless Control (WCM) - Standard Procedure).

Test Complete.

B1A28-ECM MISMATCH WITH SKIM

Possible Causes