Refer to
Power, Ground, CMP, KS, and CKP
.
Circuit Description
This engine is equipped with a distributorless ignition system called the electronic ignition (EI) system. The primary circuit of the EI system consists of 2 separate ignition coils, an electronic ignition control module (ICM) and a crankshaft position (CKP) sensor as well as the related connecting wires and the ignition control (IC) portion of the Powertrain Control Module (PCM). Each secondary circuit consists of the secondary winding of the coil, spark plug wires, and the spark plugs.
Important: The camshaft position (CMP) sensor is only used for a misfire detection and is not part of the ignition system.
Diagnostic Aids
| • | A small amount of resistance in the battery positive voltage circuit to the PCM may cause a no start. Test the battery positive voltage circuit for excessive resistance or corrosion. Refer to Wiring Repairs in Wiring Systems. |
| • | The PCM grounds will cause a NO START only if all of them are not making a good connection. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
| • | Test/Inspect the Throttle Position (TP) sensor for the following conditions: |
| - | Binding |
| - | Sticking |
| - | Intermittently shorted |
| - | Intermittently open |
| • | The ECT may be skewed within specifications and may not set a code. On a cold vehicle the ECT and IAT should be 3° C or 5° F of each other. On a HOT vehicle, let the engine cool to ambient temperature then test the ECT. |
| • | The MAP sensor may be skewed within specifications and not set a code. Refer to DTC P0105 Manifold Absolute Pressure (MAP) Sensor Performance/Range for diagnostic testing. |
| • | If the CKP sensor is loose it may cause an intermitted NO START by moving away from the reluctor wheel. Inspect the sensor and matting surface for being clean and tight. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Verify that the fuel pump runs by removing the fuel cap and listening, or by feeling the fuel rail or fuel lines on key up.
-
Repair the cause of the malfunctioning Spark plugs before replacing.
-
Inspect for basic engine malfunction like low compression, burnt valves, a worn timing chain and worn gears, etc.
-
Any time the CKP sensor is removed the Crankshaft Position Variation learn procedure must be performed.
-
The replacement PCM must be reprogrammed and the Crankshaft Position System Variation Learn procedure must be performed.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||||
2 | Are DTCs P0601, P0602, P1621, or P1629 set? | -- | ||||||||||
3 |
Does the CKP Activity Counter increment? | -- | ||||||||||
Does the fuel pump run? | -- | |||||||||||
5 |
Caution: Wrap a shop towel around the fuel pressure connection in order to reduce the risk of fire and personal injury. The towel will absorb any fuel leakage that occurs during the connection of the fuel pressure gage. Place the towel in an approved container when the connection of the fuel pressure gage is complete. Does the fuel gauge read within the specified value? | 358-405 kPa (52-58 psi) | Go to Fuel System Diagnosis | |||||||||
6 |
Was spark observed on all cylinders? | -- | ||||||||||
Did you find and correct the condition? | -- | |||||||||||
Inspect for basic engine problems. Refer to Base Engine Misfire Diagnosis in Engine Mechanical. Did you find and correct any conditions? | -- | Go to Diagnostic Aids | ||||||||||
9 |
Does the DMM read the specified value? | B+ | ||||||||||
10 |
Does the resistance measure within the specified value? | 700-1,300 ohms | ||||||||||
11 |
Does the DMM read more than the specified value? | 200 mV | ||||||||||
12 |
Does the CKP Activity Counter increment? | -- | ||||||||||
13 |
Notice: Do not leave the jumper wire connected to the PCM IC circuit connector for longer than 5 seconds at a time. Failure to do so may damage the ignition coil and/or the Ignition Control Module. Does the spark tester spark? | -- | ||||||||||
14 |
Did you find and correct the condition? | -- | ||||||||||
15 |
Did you find and correct the condition? | -- | ||||||||||
16 |
Did you find and correct the condition? | -- | ||||||||||
17 |
Did you find and correct the condition? | -- | ||||||||||
18 |
Did you find and correct the condition? | -- | ||||||||||
19 | Repair the open in the B+ and/or ground circuit. Did you complete the repair? | -- | -- | |||||||||
|
Important:: Refer to Crankshaft Position System Variation Learn . Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement . Did you complete the replacement? | -- | -- | ||||||||||
21 | Replace the ICM. Refer to Ignition Control Module Replacement . Did you complete the replacement? | -- | -- | |||||||||
22 | Replace the affected ignition coil. Refer to Ignition Control Module Replacement . Did you complete the replacement? | -- | -- | |||||||||
|
Important:: Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | -- | ||||||||||
24 | Attempt to start the engine. Does the engine start and run? | -- |
