Diagnostic Aids

WARNING: This page is about a different car, the 1995 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following:

Ignition coil packs.
Ignition coil wiring harness.
Powertrain Control Module (PCM).

1) DTC P0350, P0351, P0352, P0353 & P0354

Using a spark tester, check for spark at all spark plug wires while cranking engine. If consistent spark is present at all spark plug wires, system is okay and testing is complete. If consistent spark is not present, go to next step.

2) Check Secondary Ignition

Check spark plugs, spark plug wires and coils for damage, looseness or shorting. Repair or replace as necessary. If secondary ignition looks okay, go to next step.

3) Check For COIL PWR At Coil

Turn ignition off. Install EI Diagnostic Harness (007-00059) to Breakout Box (014-000950) and ICM. Install coil tee. Use EI (High Data Rate) 6 overlay. Connect diagnostic harness negative lead to battery negative terminal. Leave positive lead disconnected. Set diagnostic harness box type switch to "4/6" cylinder position. Turn ignition on. Measure voltage between breakout box test pins J5 (COIL PWR) and J7 (B-). If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair open in COIL PWR circuit. Clear PCM memory and repeat QUICK TEST .

WARNING: Unless otherwise instructed, PCM must not be connected to breakout box when performing ignition system testing.

4) Check C1C Circuit At Coil Pack

Turn ignition on. Measure voltage between breakout box test pins J3 (C1C) and J7 (B-). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, go to step 16).

5) Check C2C Circuit At Coil Pack

Turn ignition on. Measure voltage between breakout box test pins J6 (C2C) and J7 (B-). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, go to step 18).

6) Check C3C Circuit At Coil Pack

Turn ignition on. Measure voltage between breakout box test pins J7 (B-) and J10 (C3C). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, go to step 20).

7) Check C1I Circuit At ICM

Turn ignition off. Connect ICM wiring harness connector to diagnostic harness ICM tee. Turn ignition on. Measure voltage between breakout box test pins J7 (B-) and J26 (C1I). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C1I circuit.

8) Check C2I Circuit At ICM

Turn ignition on. Measure voltage between breakout box test pins J7 (B-) and J52 (C2I). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C2I circuit.

9) Check C3I Circuit At PCM

Turn ignition on. Measure voltage between breakout box test pins J7 (B-) and J78 (C3I). If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, repair open in C3I circuit.

10) Check C1C Circuit At Coil

Turn ignition off. Disconnect coil from diagnostic harness coil tee. Turn ignition on. Measure voltage between breakout box test pins J3 (C1C) and J7 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 22).

11) Check C2C Circuit At Coil

Leave ignition on. Measure voltage between breakout box test pins J6 (C2C) and J7 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 23).

12) Check C3C Circuit At Coil

Leave ignition on. Measure voltage between breakout box test pins J7 (B-) and J10 (C3C). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 24).

13) Check C1C Circuit At Coil While Cranking

Connect positive lead of EI Diagnostic Harness (007-00059) to battery positive terminal. Connect incandescent test light between breakout box test pins J1 (B+) and J3 (C1C). Crank engine. If test light blinks brightly once every engine revolution, go to next step. If test light does not blink as indicated, replace PCM and repeat QUICK TEST .

14) Check C2C Circuit At Coil While Cranking

Connect incandescent test light between breakout box test pins J1 (B+) and J6 (C2C). Crank engine. If test light blinks brightly once every engine revolution, go to next step. If test light does not blink as indicated, replace PCM and repeat QUICK TEST .

15) Check C3C Circuit At Coil While Cranking

Connect incandescent test light between breakout box test pins J1 (B+) and J10 (C3C). Crank engine. If test light blinks brightly once every engine revolution, replace coil pack. Clear PCM memory and repeat QUICK TEST . If test light does not blink as indicated, replace PCM and repeat QUICK TEST .

16) Check Coil No. 1

Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J3 (C1C) and J7 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace coil pack. Clear PCM memory and repeat QUICK TEST .

17) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J3 (C1C) and J7(B-). If resistance is less than 10,000 ohms, repair short to ground in C1 circuit. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST .

18) Check Coil No. 2

Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J6 (C2C) and J7 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace coil pack. Clear PCM memory and repeat QUICK TEST .

19) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J6 (C2C) and J7(B-). If resistance is less than 10,000 ohms, repair C2C circuit short to ground. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST .

NOTE: If C2 circuit is shorted to ground, coil damage may occur.

20) Check Coil No. 3

Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J7 (B-) and J10 (C3C). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace coil pack. Clear PCM memory and repeat QUICK TEST .

21) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J7 (B-) and J10 (C3C). If resistance is less than 10,000 ohms, repair C3C circuit short to ground. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST .

22) Check Coil No. 1

Turn ignition off. Disconnect PCM from diagnostic harness ICM tee. Turn ignition on. Measure voltage between breakout box test pins J3 (C1C) and J7 (B-). If DC voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If voltage is 0.5 volt or more, repair C1C circuit short to power. Clear PCM memory and repeat QUICK TEST .

23) Check Coil No. 2

Turn ignition off. Disconnect ICM from diagnostic harness ICM tee. Turn ignition on. Measure voltage between breakout box test pins J6 (C2C) and J7 (B-). If DC voltage is less than 0.5 volt, replace PCM. Clear PCM memory and repeat QUICK TEST . If voltage is 0.5 volt or more, repair C2C circuit short to power. Clear PCM memory and repeat QUICK TEST .

24) Check Coil No. 3

Turn ignition off. Disconnect ICM from diagnostic harness ICM tee. Turn ignition on. Measure voltage between breakout box test pins J7 (B-) and J10 (C3C). If DC voltage is less than 0.5 volt, replace PCM. Clear PCM memory and repeat QUICK TEST . If voltage is 0.5 volt or more, repair C3C circuit short to power. Clear PCM memory and repeat QUICK TEST .