Circuit Description
The crankshaft position (CKP) sensor is connected directly to the ignition control (IC) module. The CKP sensor consists of the following circuits:
| • | The 10-volt reference circuit |
| • | The low reference circuit |
| • | The CKP sensor 1 signal circuit |
| • | The CKP sensor 2 signal circuit |
The CKP sensor shares power supply and low reference circuits with the camshaft position (CMP) sensor.
Conditions for Running the DTC
The engine is running, and 3X reference pulses are being received.
Conditions for Setting the DTC
The 18X reference pulses are not received in 1 engine cycle, at 720 degrees of crankshaft rotation.
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
Inspect for the following conditions:
| • | Incorrect harness routing near secondary ignition components. |
| • | Faulty ignition coil--Remove the ignition coils and inspect the ignition control module and coils for cracks, for carbon tracking, or for other signs that indicate that the coil secondary circuit is arcing to the ICM or to the ICM wiring harness. Refer to Ignition Coil Replacement . |
| • | Secondary ignition wires arcing to wiring harness--Inspect the secondary ignition wires for carbon tracking or for other signs of damage. |
| • | Poor Connections--Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | ||||||||||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |||||||||
2 | Attempt to start the engine. Does the engine start and run? | -- | Go to Step 3 | Go to Step 8 | ||||||||
3 | Observe the 18X Crank Sensor parameter with the scan tool. Does the 18X Crank Sensor parameter change with engine speed? | -- | Go to Step 4 | Go to Step 5 | ||||||||
4 |
Does the DTC fail this ignition? | -- | Go to Step 5 | Go to Testing for Intermittent Conditions and Poor Connections | ||||||||
5 |
Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 6 | ||||||||
6 |
Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 7 | ||||||||
7 |
Does the 18X Crank Sensor RPM change? | -- | Go to Step 13 | Go to Step 11 | ||||||||
8 |
Is the voltage within the specified range? | 4-8 V | Go to Step 14 | Go to Step 12 | ||||||||
9 | Test the 18X reference medium resolution engine speed signal circuit between the ICM and the powertrain control module (PCM) for a short to ground. Refer to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 19 | ||||||||
10 | Test the 18X reference medium resolution engine speed signal circuit between the ICM and the PCM for a short to voltage. Refer to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 19 | ||||||||
11 | Test the 18X reference medium resolution engine speed signal circuit between the ICM and the PCM for an open. Refer to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 16 | ||||||||
12 | Test the CKP sync signal circuit for an open. Refer to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 15 | ||||||||
13 | Inspect for the following conditions:
Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 15 | ||||||||
14 | Test for an intermittent or for poor connections at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 17 | ||||||||
15 | Test for an intermittent or for poor connections at the ICM. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 18 | ||||||||
16 | Test for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 19 | ||||||||
17 | Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 20 | -- | ||||||||
18 | Replace the ICM. Refer to Ignition Control Module Replacement . Did you complete the replacement? | -- | Go to Step 20 | -- | ||||||||
19 | Replace the PCM. Refer to Powertrain Control Module Replacement for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 20 | -- | ||||||||
20 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 21 | ||||||||
21 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||
