Diagnostic Aids
NOTE:
After each service or repair procedure has been completed, reconnect all components. Clear DTCs and perform DRIVE CYCLE PROCEDURES
under ADDITIONAL SYSTEM FUNCTIONS. Ensure MISFIRE & FUEL MONITOR PROCEDURES are performed to verify repair. 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 Coil Pack
- Ignition Coil Wiring Harness
- IGN START/RUN Circuit To Coil Pack
- Powertrain Control Module (PCM)
NOTE:
Performing step 1) and comparing test results to IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK) table can help determine which coil is not firing.
IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK)
| Application & Cylinder No. | Coil Driver | PCM Terminal No. | DTC | |
|---|---|---|---|---|
| 4-Cylinder Engines | ||||
| Except Ranger 2.5L | ||||
| 1 | A | 26 | P0351 | |
| 3 | B | 52 | P0352 | |
| 4 | A | 26 | P0351 | |
| 2 | B | 52 | P0352 | |
| Ranger 2.5L | ||||
| 1 | A, C | 26, 78 | P0351, P0353 | |
| 3 | B, D | 52, 104 | P0352, P0354 | |
| 4 | A, C | 26, 78 | P0351, P0353 | |
| 2 | B, D | 52, 104 | P0352, P0354 | |
| 6-Cylinder Engines | ||||
| 1 | A | 26 | P0351 | |
| 4 | B | 52 | P0352 | |
| 2 | C | 78 | P0353 | |
| 5 | A | 26 | P0351 | |
| 3 | B | 52 | P0352 | |
| 6 | C | 78 | P0353 | |
| 8-Cylinder Engines | ||||
| 1 | A | 26 | P0351 | |
| 3 | B | 52 | P0352 | |
| 7 | C | 78 | P0353 | |
| 2 | D | 104 | P0354 | |
| 6 | A | 26 | P0351 | |
| 5 | B | 52 | P0352 | |
| 4 | C | 78 | P0353 | |
| 8 | D | 104 | P0354 | |
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 Pack) 1 | JE1 | JE1 | |||
| P0352 (Coil Pack) 1 | JE1 | JE1 | |||
| P0353 (Coil Pack) 1 | JE1 | JE1 | |||
| P0354 (Coil Pack) 1 | JE1 | JE1 | |||
|
|||||
- 1) Determine Which Cylinder Is Not Firing
Using engine analyzer, IGNITION COIL-TO-CYLINDER CORRELATION table and illustrations, determine which coil is not firing. See Fig 1-Fig 4 . Record cylinder, coil and PCM harness connector terminal number(s) and go to next step. - 2) KOER & Continuous Memory DTC P0351, P0352, P0353 & P0354: Check IGN START/RUN Voltage To Coil Pack
Disconnect suspect coil that was determined in step 1). Turn ignition switch to ON position. Using a DVOM, measure voltage between coil harness connector IGN START/RUN terminal and chassis ground. See Fig 1-Fig 4 . If voltage is more than 10 volts, turn ignition switch to OFF position and go to step 5). If voltage is 10 volts or less, 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.NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 2) to step 5). No test procedures have been omitted. - 5) Check Functionality Of Suspect Coil Driver (CD) Circuit
Connect a test light between coil harness connector IGN START/RUN terminal and suspect CD circuit terminal. See IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK) table. 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 step 11). If test light does not blink consistently, turn ignition switch to OFF position and go to next step. - 6) Check For Open In Suspect CD Circuit
Disconnect PCM connector. Using a DVOM, measure resistance of suspect CD circuit between PCM harness connector and appropriate coil harness connector. See Figure and Fig 1-Fig 4 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in appropriate CD circuit. - 7) Check Suspect CD Circuit For Short To VPWR In Harness
Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and suspect CD circuit terminal at PCM harness connector. If voltage is less than one volt, turn ignition switch to OFF position and go to next step. If voltage is one volt or more, turn ignition switch to OFF position and repair short to VPWR in CD circuit. - 8) Check Suspect CD Circuit For Short To Ground In Harness
Disconnect scan tool from DLC. Using a DVOM, measure resistance of suspect CD circuit between chassis ground and appropriate PCM harness connector terminal. 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 CD circuit. After repair is complete, check for damaged coil, go to step 10). - 9) Perform Intermittent Test On Suspect CD Circuit Harness
Connect DVOM between suspect CD circuit terminal at PCM harness connector and CD terminal at coil harness connector. See IGNITION COIL-TO-CYLINDER CORRELATION (COIL PACK) table. See Figure and Fig 1-Fig 4 . Observe DVOM for indication of fault while wiggling and bending suspect CD circuit. Start at coil connector and work toward PCM harness connector. Fault will be indicated by sudden change in DVOM resistance. If a fault is indicated, isolate fault and repair as necessary. If no fault is indicated, replace PCM. After repair is complete, check for damaged coil, go to next step. - 10) Check Suspect Coil Primary Side For Open Circuit
Using a DVOM, measure resistance of suspect coil between coil harness connector CD terminal and IGN START/RUN terminal. If resistance is less than 5 ohms, coil pack is okay. Testing is complete. If resistance is 5 ohms or more, replace coil pack. - 11) Check Suspect Coil Primary Side For Open Circuit
Using a DVOM, measure resistance of suspect coil between coil harness connector CD terminal and IGN START/RUN terminal. See Fig 1-Fig 4 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, replace coil pack. - 12) Check Coil Secondary
Disconnect both plug wires from suspect coil. Using a DVOM, measure secondary resistance of coil between coil pack towers. Resistance should be within specification. See SECONDARY COIL RESISTANCE table. If resistance is not within specification, replace coil pack. If resistance is within specification, coil is okay. If DTC P0350 is present, go to TEST JB, step 1). On all others, go to TEST Z, step 1) .
SECONDARY COIL RESISTANCE
| Application | k/Ohms |
|---|---|
| Series 5 Coil Pack | 8.6-11.1 |
| All Others | 11.5-15.5 |
Fig 1: Identifying 4-Tower Coil Pack Wiring Harness Connector Terminals (Cougar 2.0L, Escape 2.0L, Escort & Focus, & Ranger 2.3L)
Fig 2: Identifying 4-Tower Coil Pack Wiring Harness Connector Terminals (Explorer & Mountaineer 5.0L, & Ranger 2.5L)