Vehicles affected:
Chevrolet Malibu: 1997-’99 2.4L, 1997-2003 3.1L and 2004 Malibu 2.2L and 3.5L.
Symptom:
Vehicle will start and then stall. Security indicator on the dash is on. DTC P1626, P1630 and/or P1631.
Problem 1 of 3:
The Body Control Module (BCM) failed to recognize the signal from the ignition lock cylinder.
Test & Fix:
A scan tool should indicate a DTC P1626, P1630 or P1631 stored in the Powertrain Control Module (PCM). The flow chart for each code will direct a scan tool to be used to access BCM codes. This is the best way to perform diagnostics on this problem.
If using a scan tool that is not capable of retrieving BCM codes or viewing data, try the following procedure. Disconnect the wires from the ignition lock cylinder. Turn the ignition key to the Key On, Engine Off (KOEO) position. Using a voltmeter, check voltage on the white wire, at the BCM, to ground. The voltage should read 12 volts.
Then check the voltage on the yellow wire, at the BCM, to ground. This should read 5 volts. Next check the black wire, at the BCM, being sure there is a good ground on this wire.
If there is a loss of ground on the black wire or the voltage is missing on the white or yellow wires, check the power and ground for the BCM and the connections at the BCM. If powers, grounds and connections are OK, the BCM will need to be replaced.
Note: When you remove the BCM, first disconnect connector C3 before you disconnect the remaining connectors. When you re-install the BCM, connect connector C3 last. Connector C3 contains the BCM power and ground sources. If the voltages are correct, proceed to step 2.
