System Description
The camshaft position (CMP) sensor is used to correlate crankshaft to camshaft position so that the engine control module (ECM) can determine which cylinder is ready to be fueled by the injector. The CMP is also used to determine which cylinder is misfiring when a misfire is present. When the ECM cannot use the information from the CMP sensor, a DTC is set, and the ECM will fuel the engine using the alternating synchronous double fire (ASDF) method.
Conditions for Setting the DTC
| • | A CMP sensor reference pulse is not detected at the correct interval every 4 cylinders. |
| • | The engine is running. |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate after 3 consecutive trips with a fail. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
| • | A history DTC is stored. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Diagnostic Aids
An intermittent problem may be caused by a poor connection, rubbed-through wire insulation, or a wire that is broken inside the insulation.
Any circuitry that is suspected as causing the complaint should be thoroughly inspected for the following conditions:
| • | Backed-out terminals |
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed |
| • | Damaged terminals |
| • | Poor terminal-to-wire connection |
| • | Physical damage to the wiring harness |
Anytime a poor connection is present, the CMP reference activity counter will stop incrementing.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The On-Board Diagnostic System Check prompts the technician to complete some basic checks and store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
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This step determines if DTC P0341 is the result of a hard failure or an intermittent condition.
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The counter should stop incrementing with the sensor electrical connector disconnected and set a DTC P0342 with the sensor disconnected. If it still increments the ECM is malfunctioning.
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By moving the CMP sensor electrical connector, the connections at the sensor are inspected. Make sure the electrical connector remains securely fastened.
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A poor connection in any of the circuits at the CMP will cause the CMP resync counter to increment. Anytime a poor connection is present, the CMP reference activity counter will stop incrementing and the CMP resync counter will increment.
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The replacement ECM must be reprogrammed. Refer to the latest Techline procedure for ECM reprogramming.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Perform an On-Board Diagnostic System Check. Was the check performed? | -- | Go to Step 2 | ||
Is DTC P0341 set? | -- | Go to Step 3 | Go to Diagnostic Aids | |
Is the voltage near the specified value? | 5 V | Go to Step 4 | Go to Step 5 | |
Using a voltmeter, measure the voltage between the CMP sensor wiring harness connector terminal 3 and ground. Is the voltage over the specified value? | 10 V | Go to Step 6 | Go to Step 10 | |
With a test light connected to ground, probe the CMP harness connector terminal 1. Does the test light illuminate? | -- | Go to Step 8 | Go to Step 9 | |
6 | With a test light connected to B+, probe the CMP sensor harness connector terminal 2. Does the test light illuminate? | -- | Go to Step 7 | Go to Step 11 |
7 | Inspect for poor connections at the CMP sensor electrical connectors and repair as needed. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 |
Did you complete the repair? | -- | Go to Step 15 | Go to Step 14 | |
9 | Inspect the CMP signal circuit for an open or short to ground and repair as needed. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
10 | Inspect for a poor connection or open in the CMP B+ feed circuit and repair as needed. Did you find and correct the condition? | -- | Go to Step 15 | -- |
11 | Inspect for a poor connection or open in the CMP ground circuit and repair as needed. Did you find and correct the condition? | -- | Go to Step 15 | -- |
12 | Inspect for a poor connection in the CMP signal circuit terminal and repair as needed. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
13 |
Did you complete the replacement? | -- | Go to Step 15 | -- |
14 |
Did you complete the replacement? | -- | Go to Step 15 | -- |
15 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | Go to Step 16 | Go to Step 2 |
16 | Are any DTCs displayed that have not been diagnosed? | -- | Go to applicable DTC table | System OK |
