B1A28
B1A28-00-ECM MISMATCH WITH SKIM
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
For the engine to start, the Sentry Key Immobilizer (SKIM) feature of the Radio Frequency Hub (RF Hub) and the Powertrain Control Module (PCM) must successfully communicate data over the data bus. Once the RF Hub sends the message that a valid Fob-Integrated-Key (FOBIK) is being used, the PCM and RF Hub perform a "handshake" routine, encrypted with the VIN, to validate this information, and a match allows the engine to run when the ignition state transitions to Start or a remote start occurance. The repair of this fault is determined by the ability of the RF Hub and PCM to complete a successful handshake routine over the bus.
- When Monitored:
Whenever a valid FOBIK is in the vehicle and the ignition is turned to the ON position or a valid remote start is active, the RF Hub/PCM handshake takes place. The RF Hub validates that the message is sent to, and received by the PCM.
- Set Condition:
When a valid FOBIK is used and the RF Hub receives a mismatching cryptology code from the PCM as part of the routine, the RF Hub 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 RF Hub and PCM complete a successful handshake.
1. TEST FOR INTERMITTENT CONDITION
1. Turn the ignition on.
2. Using the scan tool, record and erase the RF Hub DTCs.
3. Attempt to start the engine and run for one minute (if possible).
4. With the scan tool, read the Active DTCs.
Does the scan tool display: B1A28-00-ECM MISMATCH WITH SKIM as active?
Yes
- Go To 2
No
- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test.
2. VERIFY THE VEHICLE IDENTIFICATION NUMBER (VIN) STORED IN THE POWERTRAIN CONTROL MODULE (PCM).
1. Using the scan tool, access the VIN number stored in the 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.
2. Compare the VIN displayed, with the VIN of the vehicle.
Does the VIN recorded in the PCM match the VIN of the vehicle?
Yes
- Using the scan tool, verify the VIN in the RF Hub matches the VIN of the vehicle. If it DOES, Go To 3 If it does NOT match, replace the Radio Frequency Hub (RF Hub). Prior to replacing the RF Hub, the RUN circuits must be checked at the PCM. A missing run circuit at the PCM can cause this DTC to set.
- If this vehicle is equipped with a Steering Column Lock Module (ELV) (Export) , it must also be replaced anytime the RF Hub is replaced. When replacing the RF Hub and the Steering Column Lock Module (ELV), the RF Hub MUST be programmed before the Steering Column Lock Module (ELV) is programmed. .
- Replace and program the Radio Frequency Hub (RF Hub). Radio Frequency Module (RF Hub) - Removal.
- Replace and program the Steering Column Lock Module (ELV). Shaft Lock Module - Removal
- Perform the RADIO FREQUENCY HUB (RF HUB) VERIFICATION TEST. RF Hub Verification Test
No
- Using the scan tool, perform the PCM Replaced Procedure to update the VIN in the PCM. Then, Go To 3
3. PCM STARTING DTCS
1. Use the scan tool and erase all DTCs in the RF Hub and PCM.
2. Turn the Ignition Off, and wait 15 seconds before turning the Ignition On.
3. Try to start the engine. If the engine starts, leave it run for one minute and then turn the engine off (ignition on).
4. Wait one minute, and read the active PCM DTCs.
Does the scan tool display any Starting related DTCs?
Yes
- Testing and Inspection Perform the appropriate Diagnostic Procedure.
No
- Go To 4
4. VERIFY PCM PROGRAMMING
1. Use the scan tool and erase all DTCs in the RF Hub and PCM.
2. Turn the Ignition Off, and wait 15 seconds before turning the Ignition On.
3. Wait one minute, and read the active DTCs.
Does the scan tool display: B1A28-00-ECM MISMATCH WITH SKIM as active?
Yes
- Replace and program the Powertrain Control Module. PCM/ECM Reprogramming
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Repair is complete.
- Perform the BODY VERIFICATION TEST. Body Verification Test.