Diagnostic Aids
NOTE:
After each service or repair procedure has been completed, reconnect all components. Clear DTCs and perform MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE. See DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. After drive cycle is complete, repeat QUICK TEST procedures to ensure all EEC-V systems are working properly and DTCs are no longer present.
Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following.
- Ignition Coils
- Ignition Coil Harness
- Powertrain Control Module (PCM)
NOTE:
On all models with distributorless electronic ignition, manufacturer does not recommend checking ignition timing, as faulty readings are common and timing is not adjustable.
IGNITION COIL-TO-CYLINDER CORRELATION (COIL-ON-PLUG)
| Application & Cylinder No. | Ignition Coil | Coil Driver | PCM Terminal No. | DTC | |
|---|---|---|---|---|---|
| 3.0L | |||||
| Sable & Taurus | |||||
| 1 | 1 | 1 | 26 | P0351 | |
| 4 | 4 | 2 | 52 | P0355 | |
| 2 | 2 | 3 | 78 | P0354 | |
| 5 | 5 | 4 | 1 | P0355 | |
| 3 | 3 | 5 | 27 | P0356 | |
| 6 | 6 | 6 | 53 | P0353 | |
| LS | |||||
| 1 | 1 | 1 | C-31 | P0351 | |
| 4 | 4 | 2 | C-12 | P0354 | |
| 2 | 2 | 3 | C-23 | P0352 | |
| 5 | 5 | 4 | C-22 | P0355 | |
| 3 | 3 | 5 | C-13 | P0353 | |
| 6 | 6 | 6 | C-30 | P0356 | |
| 8-Cylinder Engines | |||||
| LS | |||||
| 1 | 1 | 1 | C-31 | P0351 | |
| 5 | 5 | 2 | C-23 | P0355 | |
| 4 | 4 | 3 | C-13 | P0354 | |
| 2 | 2 | 4 | C-1 | P0352 | |
| 6 | 6 | 5 | C-12 | P0356 | |
| 3 | 3 | 6 | C-22 | P0353 | |
| 7 | 7 | 7 | C-30 | P0357 | |
| 8 | 8 | 8 | C-38 | P0358 | |
| All Others | |||||
| 1 | 1 | 1 | 26 | P0351 | |
| 3 | 3 | 2 | 52 | P0353 | |
| 7 | 7 | 3 | 78 | P0357 | |
| 2 | 2 | 4 | 104 | P0352 | |
| 6 | 6 | 5 | 1 | P0356 | |
| 5 | 5 | 6 | 27 | P0355 | |
| 4 | 4 | 7 | 53 | P0354 | |
| 8 | 8 | 8 | 79 | P0358 | |
| 10-Cylinder Engines | |||||
| 1 | 1 | 1 | 26 | P0351 | |
| 6 | 6 | 2 | 1 | P0356 | |
| 5 | 5 | 3 | 52 | P0355 | |
| 10 | 10 | 4 | 27 | P0360 | |
| 2 | 2 | 5 | 78 | P0352 | |
| 7 | 7 | 6 | 53 | P0357 | |
| 3 | 3 | 7 | 104 | P0353 | |
| 8 | 8 | 8 | 79 | P0358 | |
| 4 | 4 | 9 | 102 | P0354 | |
| 9 | 9 | 10 | 82 | P0359 | |
DTCs P0350-P0360 indicate PCM did not receive a valid IDM pulse signal from ignition module (integrated in PCM). Possible causes are:
- Open Or Shorted IGN START/RUN Circuit
- Coil Driver (CD) Circuit Open, Or Shorted To Ground Or VPWR
- Faulty Ignition Coil
- Faulty PCM
NOTE:
Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION table of fault code setting condition.
FAULT CODE SETTING CONDITION
| Fault Code | KOEO | KOER | Continuous Memory |
|---|---|---|---|
| P0351 (Coil On Plug) | JF1 | JF1 | |
| P0352 (Coil On Plug) | JF1 | JF1 | |
| P0353 (Coil On Plug) | JF1 | JF1 | |
| P0354 (Coil On Plug) | JF1 | JF1 | |
| P0355 | JF1 | JF1 | |
| P0356 | JF1 | JF1 | |
| P0357 | JF1 | JF1 | |
| P0358 | JF1 | JF1 | |
| P0359 | JF1 | JF1 | |
| P0360 | JF1 | JF1 |
- 1) Determine Which Coil Is Not Firing
Perform TEST JB and use test results, or compare DTC to IGNITION COIL-TO-CYLINDER CORRELATION (COIL-ON-PLUG) table to help determine which coil is not firing. Record cylinder, coil and PCM harness connector terminal number and go to next step. - 2) DTC P0351, P0356 & P0357: Crankshaft Position Sensor Failure
If DTC P0351, P0356 or P0357 is present, go to next step. If DTC P0351, P0356 or P0357 is not present, go to step 4). - 3) Check Crankshaft Position Sensor
Disconnect Crankshaft Position (CKP) sensor connector. Measure resistance between CKP sensor terminals. If resistance is 900-1300 ohms (LS) or 290-390 ohms (all other models), go to next step. If resistance is not as specified, replace CKP sensor. - 4) Check Functionality Of Suspect Coil Driver Circuit
Disconnect suspect coil that was determined in step 1). Connect a test light between IGN START/RUN terminal and suspect CD circuit terminal at coil-on-plug harness connector. See Fig 1 or Fig 2 . Disconnect Inertia Fuel Shutoff (IFS) switch to disable fuel pump. Observe test light while cranking engine. If test light blinks consistently, turn ignition switch to OFF position and go to next step. If test light does not blink consistently, turn ignition switch to OFF position and go to step 6). - 5) Check Functionality Of Suspect Coil
Remove suspect coil from spark plug. Install Spark Tester (D81P-6666-A) to suspect coil. Reconnect coil harness connector. Observe spark tester while cranking engine. If spark is not present, replace coil. Inspect spark plug and replace as necessary. If spark is present, check spark plug. Replace as necessary and retest. If spark plug is okay, no fault is indicated at this time. Go to TEST Z . - 6) Check IGN START/RUN Voltage To Suspect Coil
Turn ignition switch to ON position. Measure voltage between IGN START/RUN terminal at suspect coil-on-plug harness connector and chassis ground. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less on LS, go to TEST B, step 5). If voltage is 10 volts or less on all other models, check condition of related fuses/fuse links. If fuse/fuse links are blown, check for short to ground in IGN START/RUN circuit. Repair as necessary. If fuse/fuse links are okay, repair open in IGN START/RUN circuit. - 7) Check Suspect CD Circuit For Open In Harness
Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Measure resistance of suspect CD circuit between PCM connector and appropriate coil-on-plug harness connector. See Fig 1 or Fig 2 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in CD circuit. - 8) Check Suspect CD Circuit For Short To Power In Harness
Turn ignition switch to ON position. Measure voltage of suspect CD circuit between appropriate PCM connector terminal and negative battery terminal. Refer to IGNITION COIL-TO-CYLINDER CORRELATION (COIL-ON-PLUG) table. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to VPWR in affected CD circuit. See WIRING DIAGRAMS article. - 9) Check Suspect CD Circuit For Short To Ground In Harness
Turn ignition switch to OFF position. Disconnect scan tool from DLC. Measure resistance of suspect CD circuit between appropriate PCM connector terminal and chassis ground. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in affected CD circuit. If symptom or DTC still exists after repair is complete, go to step 11) to check for damaged coil. - 10) Perform Intermittent Test On Suspect CD Circuit Harness
Using a DVOM, measure resistance of CD circuit between PCM harness connector and coil-on-plug harness connector. See Fig 1 or Fig 2 . Observe DVOM for indication of fault while wiggling and bending suspect CD circuit. Start at coil-on-plug harness connector and work toward PCM harness connector. Fault will be indicated by sudden change in resistance. If a fault is indicated, isolate fault and repair as necessary. If no fault is indicated, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If symptom or DTC still exists after repair is complete, go to next step to check for damaged coil. - 11) Check Suspect Coil
Remove suspect coil from spark plug. Install Spark Tester (D81P-6666-A) to suspect coil. Reconnect coil harness connector. Observe spark tester while cranking engine. If spark is not present, replace coil. Inspect spark plug and replace as necessary. If spark is present, check spark plug. Replace as necessary and retest. If spark plug is okay, no fault is indicated at this time. Go to TEST Z .