No Response From ACM
WARNING:
Occupant Restraint Controller (ORC) retains energy for up to 2 minutes after battery is disconnected. Air bag may deploy. Wait at least 2 minutes after disconnecting battery in following test.
CAUTION:
Caution should be used when servicing air bag system components. For air bag system component removal and installation procedures, see AIR BAG RESTRAINT SYSTEMS article in RESTRAINTS.
NOTE:
After making any repairs, perform AIR BAG VERIFICATION TEST under VERIFICATION TESTS unless instructed otherwise in following steps.
WARNING:
When reconnecting airbag system components, the ignition must be turned off and the battery must be disconnected.
- Ensure that the battery is fully charged. Disconnect the ACM harness connector. See Fig 1. Turn the ignition on and then reconnect the battery. Using a 12-volt test light connected to ground, probe the fused ignition switch output (run) circuit and the fused ignition switch output (run/start) circuit at the ACM connector. If the test light is illuminated on both circuits, go to the next step. If the test light is not illuminated on both circuits, repair the fused ignition switch output (run) and fused ignition switch output (run/start) circuits for an open.
- Ensure that the battery is fully charged. Disconnect the ACM harness connector. Using a 12-volt test light connected to 12 volts, probe the ground circuit. If the test light is illuminated, go to the next step. If the test light does not illuminate, repair the ground circuit for an open.
- Disconnect the ACM harness connector. Turn the ignition on and then reconnect the battery. Use Scope Input Cable (CH7058), Cable-To-Probe Adapter (CH7062), and the Red and Black test probes. Connect the Scope Input Cable to the channel one connector on the DRBIII. Attach the Red and Black leads and the Cable-To-Probe Adapter to the Scope Input Cable. With the DRBIII select PEP MODULE TOOLS. Select LAB SCOPE. Select LIVE DATA. Select 12 VOLT SQUARE WAVE. Press F2 for scope. Press F2 and use the down arrow to set voltage range to 20 volts. Set Probe to x10. Press F2 again when complete. Connect the Black lead to the chassis ground. Connect the Red lead to the PCI bus circuit in the ACM connector. Observe the voltage display on the DRBIII lab scope. If the voltage pulses from 0 to approximately 7.5 volts, go to the next step. If the voltage does not pulse from 0 to approximately 7.5 volts, repair the PCI bus circuit for an open.
- If there are no possible causes remaining, replace the Airbag Control Module (ACM). See AIR BAG CONTROL MODULE (ACM) under REMOVAL & INSTALLATION in appropriate AIR BAG RESTRAINT SYSTEMS article in RESTRAINTS.
NOTE:
One open circuit will not cause a NO RESPONSE condition.
NOTE:
Make sure test light is connected to the Battery positive terminal.
NOTE:
Ensure there is PCI bus communication with other modules. If no communication exists, see no response from PCM (PCI BUS) and repair as necessary. See PCI BUS COMMUNICATION FAILURE .