B1A28

B1A28-ECM MISMATCH WITH SKIM

For a complete wiring diagram REFER to DIAGRAMS/ELECTRICAL .

Theory of Operation


For the engine to start, the Sentry Key Immobilizer (SKIM) feature of the Wireless Ignition Node (WIN) and the Powertrain Control Module (PCM) must successfully communicate VIN data over the data bus. Once the WIN sends the message that a valid fobik is being used, the PCM and WIN perform a "handshake" routine to validate this VIN information, and a match allows the engine to run when the ignition state transitions to START. The repair of this fault is determined by the ability of the WIN and PCM/ECM to complete a successful VIN handshake routine over the bus.


- When Monitored:
Whenever a valid fobik is inserted in the base station and turned to the ON position, the WIN/PCM handshake takes place. The WIN validates that the message is sent to, and received by the PCM.

- Set Condition:
When a valid fobik is used and the WIN receives a mismatching VIN from the PCM as part of the routine, the WIN will send the command to flash the Security warning lamp and set this DTC as active. The engine will not start and the DTC will remain active until the WIN and PCM complete a successful handshake.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview


Diagnostic Test


1. DETERMINE ACTIVE OR STORED DTC
Is the DTC active or stored?

WIN - ACTIVE DTC


- Go To 2


WIN - STORED DTC


- Perform the THEFT AND SECURITY SYSTEMS INTERMITTENT TEST.Symptom Related Diagnostic Procedures


2. VERIFY THE VIN STORED IN THE POWERTRAIN CONTROL MODULE (PCM).

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.

With the scan tool, access the VIN number stored in the PCM.
Compare the VIN displayed, with the VIN of the vehicle.
Does the VIN recorded in the PCM match the VIN of the vehicle?

Yes

NOTE: Technicians must use the scan tool to perform the WIN Programming procedure after a module replacement.
Replace the Wireless Ignition Node.
- Perform the THEFT AND SECURITY SYSTEMS VERIFICATION TEST.Theft and Security System Verification Test


No


- Using the scan tool, perform the PCM Replaced Procedure to update the VIN in the PCM. Then, Go To 3


3. VERIFY PCM PROGRAMMING
Use the scan tool and erase all codes in the WIN and PCM.
Turn the Ignition Off, and wait 15 seconds before turning the Ignition On.
Wait one minute, and read active WIN codes.
Does the scan tool display this DTC as active?

Yes


- Replace and program the Powertrain Control Module.
- Perform the THEFT AND SECURITY SYSTEMS VERIFICATION TEST.Theft and Security System Verification Test


No


- Repair is complete.
- Perform the THEFT AND SECURITY SYSTEMS VERIFICATION TEST.Theft and Security System Verification Test