Circuit Description
The crankshaft position (CKP) sensor sends a reference signal to the engine control unit (ECU) in order to indicate the engine rpm. Loss of this signal or intermittent operation of the CKP sensor will set a DTC 41.
This DTC will run in the CNG or gasoline operation mode. It may trigger an ECU DTC before a PCM DTC since the AF ECU is slightly more sensitive to a marginal CKP sensor.
This is a type A DTC.
Conditions for Setting the DTC
| • | The engine is cranking or running. |
| • | The indicated rpm is equal to zero and a camshaft position (CMP) sensor signal is received. |
| • | The MAP is less than 105.23 kPa (15 psi). |
Action Taken When the DTC Sets
The ECU will turn ON the MIL and default to gasoline operation when one failure has occurred, even if it is intermittent. The vehicle will not attempt to run on CNG again until the next key cycle.
Conditions for Clearing the MIL/DTC
The ECU turn the MIL OFF after three consecutive driving trips without a fault condition present. A DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 40°C (72°F) from the start-up coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during that same ignition cycle) or the code clearing procedure has been used.
Diagnostic Aids
Always diagnose ANY PCM codes that are present before beginning this diagnostic procedure.
Inspect for the following conditions:
| • | A poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation may cause an intermittent problem. |
| • | Inspect the harness connectors for the following conditions: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | A poor terminal to wire connection |
| - | Physical damage to the wiring harness |
| • | An intermittent condition can also be the result of a defective reluctor wheel. Remove the crankshaft sensor and inspect the reluctor wheel through the hole. Inspect the porosity and the condition of the wheel. Refer to Engine Mechanical -- 2.2L in the J Platform Service Manual. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
This step determines if DTC 41 is the result of a hard failure or an intermittent condition.
-
This step allows the PCM to run diagnostics on the CKP sensor and inspect the integrity of the circuit and the sensor.
-
This step determines if the ECU is receiving the crankshaft position (CKP) sensor pulses. The normal frequency reading obtained on a fully warmed-up idling engine is between 75 hZ and 105 hZ. If a signal is present and not within this range, a circuit or a sensor problem may exist.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the AF Powertrain OBD System Check performed? | -- | Go to Step 2 | Go to Alternative Fuels (AF) Powertrain On Board (OBD) System Check |
Does the vehicle start and continue to run on CNG? | -- | Go to Diagnostic Aids | Go to Step 3 | |
3 |
The fuel indicator light will remain OFF due to the removal of the CNG system fuse. Does the vehicle start and continue to run on gasoline? | -- | Go to Step 4 | Go to DTC P0335 Crankshaft Position Sensor Circuit in Engine Controls - 2.2L in the J Platform Service Manual |
Is the action complete? | 5 minutes | Go to Step 5 | -- | |
5 | Are there any powertrain DTCs displayed that have not been diagnosed? | -- | Go to the applicable powertrain DTC table | Go to Step 6 |
Is the CKP sensor signal present at the ECU while the engine is running? | -- | Go to Step 8 | Go to Step 7 | |
7 | Inspect for an open in the CKP sensor circuit between the CKP sensor connector and C003. Was a problem found? | -- | Go to Step 9 | Go to Diagnostic Aids |
8 |
Was a problem found? | -- | Go to Step 9 | Go to Step 10 |
9 | Repair the circuit as necessary. Refer to Wiring Repairs in Engine Controls - 2.2L in the J Platform Service Manual. Is the action complete? | -- | Go to Step 11 | -- |
10 | Replace the ECU. Refer to Engine Control Unit Replacement . Is the action complete? | -- | Go to Step 11 | -- |
11 |
Did the diagnostic run and pass? | -- | Go to Step 12 | Go to Step 2 |
12 | Are any ECU or PCM DTCs displayed that have not been diagnosed? | -- | Go to the applicable DTC table | System OK |
