Symptom Related Diagnostic Procedures
Anti-Theft - Passive
Anti-Theft - Passive
Ignition Fails to Operate
Check that the key is correctly inserted into the start control unit (SCU) and that it is the correct key for the vehicle (Key will be ejected from the SCU if it is not programmed or from another vehicle). If the vehicle is an automatic, ensure that the Park position is selected and if manual, ensure it is in the Neutral position.
Check that the start button circuit to the Central Junction Box (CJB) is not open circuit or short to ground.
Check that the CAN network is not malfunctioning, i.e. open circuit or short circuit. This would mean that the CJB, ECM and Instrument Cluster would be unable to communicate. Check these modules for related DTCs and refer to relevant DTC Index.
Engine Fails to Crank
The immobilizer status indication LED is displayed in the bottom left of the instrument pack. When the key is inserted into the SCU, the LED will be turned on for 3 seconds and then turned off. The LED will flash slowly (once every 2 seconds) if the vehicle is immobilised (transponder not approved). Additionally the diagnostic system should be used to check for Diagnostic Trouble Codes (DTCs) from the CJB, instrument cluster, ECM and the ABS module.
One potential occurrence for the vehicle failing to crank on an Automatic Transmission could be due to the Locked in park switch.
Check the Crank request circuit from the CJB to ECM for short circuit or open circuit. Check the Starter Relay Circuit.
Check that the Steering Column Lock (SCL) is operating correctly. Inserting the key should drive the SCL to un-lock and steering wheel should move freely.
Check the CAN network is not malfunctioning, i.e. the CAN circuit is open or short circuit. This would mean that the CJB, instrument cluster, ECM or ABS module would not be able to communicate resulting in no challenge being made from the modules for the Immobilisation data.
Also on an Automatic, check the CAN network between the CJB and the Transmission Control Module (TCM). The CJB uses the "LockedInP" signal transmitted by the TCM to determine if the transmission is in Park before allowing crank, the CJB uses a value of 0x01, if the CJB sees a value less than this it will not allow crank, and key will not be ejected from SCU.
For a manual gearbox the clutch pedal has to be de-pressed, hence check the CAN network between the CJB and the ECM to ensure the clutch is depressed, ClutchPedalSwitch75pct = TRUE and ClutchPedalPressed2 = True. The Vehicle will not crank until these signals are set.
On an Automatic vehicle, check the CAN network between the ABS module and the CJB. The CJB uses a signal "BrakePedalActive" to determine if the brake pedal has been depressed in order to allow the engine to crank. The CJB uses a value = TRUE if the CJB does not receive this signal, it will not allow the crank request output.
Engine Cranks But Will Not Start
If the engine is cranking it means that the EMS has passed the authorisation required with the CJB. If this authorisation failed, the ECM would not engage the starter relay. This could be confirmed by verifying the LED in the left of the Instrument pack being illuminated for 3 seconds on Key insertion, or by reading DTCs from the CJB or the ECM.
In all cases of suspected non-start issues, the most logical failure modes should be eliminated first. i.e.
1. Check all relevant supplies and grounds to the relevant modules are ok.
2. Note any unusual behaviour from other systems/functionality.
3. Note any functions that are not operating as expected.