Circuit/System Testing

NOTE: Do not perform this diagnostic procedure if you were not sent here from a misfire DTC or the Engine Cranks but Does Not Run diagnostic.

Ignition OFF, disconnect the harness connector of the affected T8 ignition coil.
Ignition ON, load test for battery voltage between the ignition voltage circuit terminal D or 2 and ground.
- If less than B+, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition voltage circuit and replace as necessary.
Crank or start the engine. Test for 200-400 mV between the appropriate ignition control circuit terminal C or 1 and ground.
- If less than the specified value, test the ignition control circuit for a short to ground or an open/high resistance. If the circuit/connection tests normal, replace the K20 ECM.
- If greater than the specified value, test the ignition control circuit for a short to voltage. If the circuit/connection tests normal, replace the K20 ECM.
Ignition OFF for 90 s or until the ECM powers down, test for less than 5 Ω between the low reference circuit terminal B or 3 and the K20 ECM housing.
- If greater than the specified value, test for an open/high resistance in the low reference circuit. If the circuit/connection tests normal, replace the K20 ECM.
Test for less than 5 Ω between the ground circuit terminal A or 4 and ground.
- If greater than the specified value, test for an open, or high resistance in the ground circuit.
Remove the T8 ignition coil from the engine. Connect the harness.
Remove the fuse for the fuel pump or the fuel pump control module, if equipped.
Crank the engine and test for strong spark using the EL 26792: Tester.
- If no spark or weak spark is observed, replace the T8 ignition coil.