Chart A-4, "Check Engine" Light Inoperative
NOTE:
There should be a steady "CHECK ENGINE" light when ignition is on and engine is stopped.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- 1) This checks for blown gauges fuse or open in "CHECK ENGINE" light circuit, including IP connector, remote light driver circuit and "CHECK ENGINE" light. Normal response is light on.
- 2) This checks for a shorted ECM. Grounding ECM terminal No. 2 will turn the "CHECK ENGINE" light off. If disconnecting ECM turns light on, ECM is shorted.
- 3) This test checks for grounded wire from terminal "C" of light driver to terminal No. 2 of ECM, an open circuit to terminal "B" of light driver, a bad ground or faulty light driver. A normal reading is about 9-11 volts. A reading over 11 volts indicates a bad ground or faulty light driver.
- 4) This step checks for an open in wire to terminal "B". Normal voltage is approximately battery voltage.
- 4A) This step checks for an open wire from terminal "E" to "CHECK ENGINE" light. With terminal "E" grounded, test light should light. Light off indicates an open, where light on indicates faulty light driver connection or light driver.
- 5) This test checks for grounded wire from driver terminal "C" to ECM terminal No. 2. Normal response is light on.