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Coil On Plug Test

New 01/28/2005


Welcome back. My COP hurts when I cough. What should I do?

Jim
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Thanks for the welcome.

I just had a COP or Coil Per Plug (CPP) as it is officially know, fail completely. No doubt it was missing.

Took some readings and the primary side read 8 ohms and the primary to secondary around 5k ohms. Looking into this further I found the following:

coil pin B+ to the coil spring, 4K and 10K ohms
coil pin Coil Driver (primary ground) to coil pin B+, 0.3 and 0.8 ohms.

So the coil was for sure bad. Put it on a fast cycling SS relay at work and soon had smoke coming out of it. So I sawed it in half to see what was inside one of these little jewels and can say it is mostly epoxy. If the coil were to be shorting through the case it is at the bottom on the back side of it where the iron core is closest to the valve cover.

Here's a couple of pictures of the innards.



The two brass parts at the top are the pins for the primary input. At the bottom is a brass tab, that is cut off, where the spring attaches and is the secondary output.




The shiny center point is actually the iron core.

Here is the official Ford test procedure for the CPPs on out cars. Found out too that Ford made some of their other coils with reverse polarity for the primary input. The coils are marked B+ on the 12V + pin.

Here is the official test procedure enclosed in the Word Doc. Funny too that the usual P301-308 codes one gets when dealing with coil failure deal with fuel issues. The actual coil failure codes are P351-358 which did not show up for me.

Paul Nimz
 

   

JF: Integrated Ignition Coil On Plug Coil 1 Through 10 Failure

  JF: Introduction  


 

JF1 PRELIMINARY CHECKS ON COIL, PLUGS AND BOOTS

 

Note: Electronic Ignition engine timing is entirely controlled by the PCM. Electronic Ignition engine timing is NOT adjustable. Do not attempt to check base timing. You will receive false readings.

Are coils, spark plugs and harnesses OK?

Yes

No

If no misfire DTC P0301 through P0310 present, GO to JF6 .

If any misfire DTC P0301 through P0310 present, GO to JF20 .

SERVICE or REPLACE damaged component. REMOVE all test equipment. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

 

 

JF2 CHECK COIL RESISTANCE FROM COIL PINS TO SPRING TERMINAL

Are both resistances between 4K and 10K ohms?

Yes

No

GO to JF3 .

REPLACE coil. REMOVE all test equipment. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

 

JF3 CHECK COIL RESISTANCE BETWEEN COIL PINS

Is resistance between 0.3 and 0.8 ohms?

Yes

No

GO to JF4 .

REPLACE coil. REMOVE all test equipment. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

 

JF4 CHECK COIL DRIVER LINE RESISTANCE

Is resistance less than 5 ohms?

Yes

No

Go to JF5 .

Coil driver circuit damage. SERVICE or REPLACE harness. REMOVE all test equipment. RECONNECT all components. RERUN Quick Test .

 

JF5 CHECK COIL B+ LINE RESISTANCE

Is voltage greater than 10 volts?

Yes

No

RECONNECT PCM and coil. GO to JF6 .

Coil B+ line or fuse open or short. SERVICE or REPLACE harness or fuse. REMOVE all test equipment. RECONNECT all components. RERUN Quick Test .

 

JF6 CHECK FOR COIL DTCs P0351, P0352, P0353, P0354, P0355, P0356, P0357, P0358, P0359 or P0360

Is any coil DTC P0351 through P0360 present in Continuous Memory?

Yes

No

Cylinder Coil fault. GO to JF8 .

GO to JF7 .

 

JF7 CHECK FOR DTC P0340 AND P0350

Is DTC P0340 present along with DTC P0350 in Continuous Memory?

Yes

No

Camshaft Position fault. GO to DR1 .

GO to HD5 .

 

JF8 CYLINDER COIL FAULT. CHECK FOR POWER TO THE COIL

Key off.

Install Electronic Ignition (EI) System Adapter (EDIS Systems Adapter) to 60-pin breakout box.

Install Coil/CKP connector (black) to the coil and the harness connector (green) to the harness identified by the Continuous Memory DTC (example: P0356 is cylinder 6).

Connect EI diagnostic negative lead to battery negative post.

Use Integrated Electronic Ignition Coil On Plug overlay (Rotunda T97L-50-A2 or equivalent).

Set EI harness type switch to 8 cylinder position.

Key on, engine off.

When making voltage checks, a ground reading means any value within a range of 0 to 1 volt. Also VPWR or COIL PWR readings mean any value that falls within a range of B+ to 2 volts less than B+.

Measure voltage between J7 (B-) at the EI breakout box and

5.4/6.8L: J32 (COIL-) at the EI breakout box.

3.4/4.6L: J31 (COIL+) at the EI breakout box.

Is DC voltage reading greater than 10.0 volts?

Yes

No

GO to JF9 .

COIL PWR is open to coil. CHECK connectors. SERVICE or REPLACE harness. REMOVE all test equipment. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

 

JF9 CHECK FOR COIL HIGH AT COIL

Key on, engine off.

Measure voltage between J7 (B-) at the EI breakout box and

5.4/6.8L: J31 (COIL+) at the EI breakout box.

3.4/4.6L: J32 (COIL-) at the EI breakout box.

Is dc voltage reading greater than 10.0 volts?

Yes

No

GO to JF10 .

Coil low fault. GO to JF13 .

 

JF10 CHECK FOR COIL HIGH AT PCM

Key on, engine off.

Measure voltage between J7 (B-) at the EI breakout box and the 104 pin breakout box Test Pin number identified in the following chart according to engine cylinder number:

104 PIN BREAKOUT BOX COIL DRIVER (CD) TEST PIN NUMBER

Engine

26

52

78

104

1

27

53

79

3.4L SHO

1

5

4

2

6

3

7

8

4.6L/ 5.4L

1

3

7

2

6

5

4

8



 

104 PIN BREAKOUT BOX COIL DRIVER (CD) TEST PIN NUMBER

Engine

26

1

52

27

78

53

104

79

102

82

6.8L 10 Cyl.

1

6

5

10

2

7

3

8

4

9

 

Is dc voltage reading greater than 10.0 volts?

Yes

No

GO to JF11 .

Coil is open. CHECK connectors. SERVICE or REPLACE harness. REMOVE all test equipment. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

 

JF11 CHECK FOR COIL LOW AT COIL CONNECTOR

Key off.

Disconnect coil from Coil/CKP connector, leave EI diagnostic harness connected to vehicle harness.

Key on, engine off.

Measure voltage between J7 (B-) at the EI breakout box and

5.4/6.8L: J31 (COIL+) at the EI breakout box.

3.4/4.6L: J32 (COIL-) at the EI breakout box.

Is dc voltage reading less than 0.5 volts?

Yes

No

GO to JF12 .

Coil high fault. GO to JF15 .

 

JF12 CHECK COIL AT COIL CONNECTOR WHILE CRANKING

Coil disconnected from EI diagnostic harness. EI diagnostic harness connected to vehicle harness.

Connect EI diagnostic harness positive lead to battery.

Connect an incandescent test lamp between J1 (B+) at the EI breakout box and

5.4/6.8L: J31 (COIL+) at the EI breakout box.

3.4/4.6L: J32 (COIL-) at the EI breakout box.

Crank engine.

Does lamp blink consistently and brightly, one blink per engine revolution?

Yes

No

GO to JF13 .

Coil is open. REPLACE PCM. REMOVE all test equipment. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

 

JF13 CHECK FOR COIL SHORT LOW

Key off.

Disconnect coil from Coil/CKP connector, leave EI diagnostic harness connected to vehicle harness coil connector.

Measure voltage between J7 (B-) at the EI breakout box and

5.4/6.8L: J31 (COIL+) at the EI breakout box.

3.4/4.6L: J32 (COIL-) at the EI breakout box.

Is the resistance reading less than 2K ohms?

Yes

No

GO to JF14 .

Coil is open. REPLACE coil. REMOVE all test equipment. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

 

JF14 CHECK FOR COIL SHORT LOW IN PCM

Key off.

Coil disconnected from EI diagnostic harness. EI diagnostic harness connected to vehicle harness.

Disconnect PCM from vehicle harness.

Measure voltage between J7 (B-) at the EI breakout box and

5.4/6.8L: J31 (COIL+) at the EI breakout box.

3.4/4.6L: J32 (COIL-) at the EI breakout box.

Is the resistance reading greater than 10K ohms?

Yes

No

Coil shorted low. REPLACE PCM. REMOVE all test equipment. RECONNECT all components. RERUN Quick Test .

Coil shorted low. CHECK connectors. SERVICE or REPLACE harness. REMOVE all test equipment. RECONNECT all components. RERUN Quick Test .

 

JF15 CHECK FOR COIL SHORT HIGH

Key off.

Coil disconnected from EI diagnostic harness. EI diagnostic harness connected to vehicle harness.

Disconnect PCM from vehicle harness.

Measure voltage between J7 (B-) at the EI breakout box and

5.4/6.8L: J31 (COIL+) at the EI breakout box.

3.4/4.6L: J32 (COIL-) at the EI breakout box.

Is dc voltage reading less than 0.5 volt?

Yes

No

Coil shorted high. REPLACE PCM. REMOVE all test equipment. RECONNECT all components. RERUN Quick Test .

Coil shorted high. CHECK connectors. SERVICE or REPLACE harness. REMOVE all test equipment. RECONNECT all components. RERUN Quick Test .

 

JF20 DTC P0351, P0356 AND P0357: CRANKSHAFT POSITION SENSOR FAILURE

Are any of the above listed DTCs present?

Yes

No

GO to JF21 .

GO to JF2 .

 

JF21 CHECK RESISTANCE OF CRANKSHAFT POSITION SENSOR

Measure resistance of Crankshaft Position Sensor.

Is resistance between 290 and 390 ohms?

Yes

No

Crankshaft Position Sensor OK, GO to JF2 .

REPLACE Crankshaft Position Sensor. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .

 

 

HD40 CHECK CMP SENSOR OUTPUT

Diagnostic Trouble Code (DTC) P1309 indicates Misfire Detection Monitor is not enabled.

Key off.

Breakout box installed, PCM disconnected.

Connect digital multimeter between Test Pin 85 (CMP) and Test Pins 51 or 103 (PWR GND) at the breakout box.

Bump engine in short burst with the starter without starting engine for at least 10 engine revolutions.

Does digital multimeter reading switch between low (less than 2.0 volts DC) and high (greater than 8.0 volts DC)?

Yes

No

Note: A Hall effect type CMP sensor that is installed out of synchronization will produce a DTC. VERIFY the correct installation by referring to the Powertrain/Engine Group in the Service Manual. If the CMP is installed properly, REPLACE PCM. REMOVE breakout box. RECONNECT all components. RERUN Quick Test .

 

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Bet your'e glad you made that wisecrack to Paul eh Jim???

U.L.


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