Test 5 - "Check Engine" Light Inoperative
- With ignition on and engine stopped, ground terminal A of ALDL. See Fig 1
. If light comes on, go to step 2). If light is off, check for failed gauge fuse, open in wire from ALDL, failed bulb or connection.
- Check voltage from remote lamp driver terminal C to ground. If voltage is less than 6 volts, go to step 3). If voltage is 6-11 volts, go to step 5). If voltage is greater than 11 volts, check for open from lamp driver terminal D to ground. If okay, replace lamp driver.
- Check voltage from driver terminal B to ground. If voltage is greater than 10 volts, go to step 4). If voltage is less than 10 volts, repair open in circuit to gauge fuse from terminal B.
- Remove wire from driver connector terminal C and reconnect driver. If "Check Engine" light is on, repair ground wire from driver terminal C to ECM terminal No. 4. If "Check Engine" light is off, driver or connections are faulty.
- Ground driver terminal E. If "Check Engine" light is on, driver or connections are faulty. If "Check engine" is off, repair open in wire to driver terminal E.
Courtesy of GENERAL MOTORS CORP.