PCM Mismatch with SKIM
B1A28 - PCM Mismatch with SKIM
For a complete wiring diagram, refer to.
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 Fob-in-Key (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 WIN Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Wireless Ignition Node Pre-Diagnostic Procedure
Test Step 1 - Determine Active or Stored DTC
• 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. 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.
Is the DTC active or stored?
WIN - Active DTC
• Go to Test Step 2
WIN - Stored DTC
• Perform the WIN Intermittent Test. Refer to => Non-DTC Based Diagnostics. Wireless Ignition Node Intermittent Test
Test Step 2 - Verify the VIN Stored in the PCM
• 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 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
• Replace the wireless ignition node.
• Perform the WIN Verification Test. Refer to => Non-DTC Based Diagnostics. Wireless Ignition Node Verification Test
• Technicians must use the scan tool to perform the WIN Programming procedure after a module replacement.
No
• Using the scan tool, perform the PCM replaced procedure to update the VIN in the PCM. Then, go to
Test Step 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 PCM.
• Perform the WIN Verification Test. Refer to => Non-DTC Based Diagnostics. Wireless Ignition Node Verification Test
No
• Repair is complete.
• Perform the WIN Verification Test. Refer to => Non-DTC Based Diagnostics. Wireless Ignition Node Verification Test