Volvo Troubleshooting Questions? Ask a Mechanic for Answers ASAP
It sounds like the column lock module or the start control module is acting up. The lock module can sometimes be reprogrammed by the dealer, but most of them need to be replaced when they start doing that. Another common issue is the start control module.
Here are the procedures to diagnose the steering column lock module (try #2 first):
1. Read through Tech-Net Note (TNN) 30-07 for information on the immobilizer system.2. Have the customer try a different key when acting up. Also ensure the customer doesn't have other transponder equipped keys on the key ring, as this can cause interference.3. Check fuse F23 (10amp).4. You will need a scan tool to read codes and key position through the Central Electronic Module (CEM).5. The Start Control Unit (SCU) has been the most common problem. This module is plug and play with no software required.6. If there are codes for communication with the SCU and the Steering Column Lock Module (SCL) is not unlocking or locking, disconnect the Steering Column Lock Module (SCL). This can affect communication between the SCU and the CEM. The engine will not crank with it disconnected, but you can check codes to see if the SCU communication code is gone after disconnecting the SCL. If the SCL is replaced, software must be downloaded to the vehicle to program the SCL.7. If the battery went dead or low when this started, remove both cables and touch together, charge the battery and recheck. This system is very sensitive to battery voltage and modules can logic lock when this happens. Doing a battery reset usually makes all functions resume normally.8. Check all connections at the Central Electronic Module (CEM), under the passenger's side of the dash. The connectors will commonly become unclipped and disconnect.9. Check grounds 31/83 for the SCU and 31/84 for the CEM. 31/83 is located in the driver's side kick panel and 31/84 is located in the passenger's side kick panel.10. Check for communication with the Brake Control Module (BCM), Transmission Control Module (TCM) and the Engine Control Module (ECM). A loss of communication can cause a no crank situation.
Let me know if you need any diagrams while/after looking into these items.