For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provide an overview of each diagnostic category.

### DTC Descriptors

DTC P0335: Crankshaft Position (CKP) Sensor Circuit
DTC P0336: Crankshaft Position (CKP) Sensor Performance
DTC P0337: Crankshaft Position (CKP) Sensor Circuit Low Duty Cycle
DTC P0338: Crankshaft Position (CKP) Sensor Circuit High Duty Cycle

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
CKP Sensor Signal | P0335 | P0335 | P0335 | P0336
Low Reference | -- | P0335 | P0335, P0338 | P0336
Shielded Ground | -- | -- | -- | P0336

### Circuit/System Description

The crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. The CKP sensor produces an AC voltage of different amplitude and frequency. The frequency depends on the velocity of the crankshaft, and the AC voltage output depends on the crankshaft position and battery voltage. The CKP sensor works in conjunction with a 58X reluctor wheel attached to the crankshaft. The engine control module (ECM) can synchronize the ignition timing, fuel injector timing, and spark knock control based on the CKP and the camshaft position (CMP) sensor inputs. The CKP sensor is also used to detect misfire and tachometer display. The CKP sensor circuits are connected directly to the ECM. The circuits between the CKP sensor and the ECM consist of the following circuits:

• | The signal

• | The low reference

• | The shielded ground

### Conditions for Running the DTC

#### P0335

• | The engine is cranking or operating.

• | The ECM has detected more than 8 camshaft revolutions.

• | The DTC runs continuously once the above conditions are met.

#### P0336

• | The engine is cranking or operating.

• | The ECM has not detected a reverse turn in the engine revolutions.

• | The DTC runs continuously once the above conditions are met.

#### P0337

• | The engine is cranking or operating.

• | The idle speed is 50 RPM greater than desired idle speed.

• | The DTC runs continuously once the above conditions are met.

#### P0338

• | The engine is cranking or operating.

• | The vehicle speed is less than 1 km/h (0 mph) or greater than 25 km/h (15 mph).

• | The DTC runs continuously once the above conditions are met.

### Conditions for Setting the DTC

#### P0335

• | The ECM does not detect a signal from the CKP sensor.

| OR

• | The ECM detects a CKP signal with out reference pulse for more than 10 revolutions.

#### P0336

• | The ECM detects a 25 RPM engine speed fluctuation 10 or more times during an ignition cycle.

| OR

• | The ECM detects 1100 or more interruptions in the engine speed signal during an ignition cycle.

#### P0337

The ECM detects 215 or more interruptions in the engine speed signal during an ignition cycle.

#### P0338

The ECM detects 215 or more interruptions in the engine speed signal during an ignition cycle.

### Action Taken When the DTC Sets

DTCs P0335, P0336, P0337, and P0338 are Type A DTCs.

### Conditions for Clearing the DTC

DTCs P0335, P0336, P0337, and P0338 are Type A DTCs.

### Diagnostic Aids

The following conditions could also set the DTCs:

• | Physical damage to the CKP sensor or the reluctor wheel

• | Excessive play or looseness of the CKP sensor or the reluctor wheel

• | Improper installation of the CKP sensor or the reluctor wheel

• | Foreign material passing between the CKP sensor and the reluctor wheel

• | Excessive air gap between the CKP sensor and the reluctor wheel

• | The ECM uses the camshaft position sensor to determine engine speed and position when there is a CKP sensor condition.

• | The engine will operate with a CKP sensor condition only if the ECM has stored the learned reference position of the camshafts in memory. With a crankshaft position sensor condition the engine will go into a limp home mode after a hard restart. The ECM then calculates engine speed from one of the camshaft position sensors. During a limp home mode, DTC P0324 may set and should be ignored.

• | An intermittent condition in the camshaft position (CMP) sensor circuits can cause a CKP DTC to set. Inspect the CMP sensor, harness connections, and related wiring, if you suspect this condition.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls Connector End Views

#### Description and Operation

Electronic Ignition (EI) System Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Attempt to start the engine, observe the scan tool DTC information parameter. DTCs P0335, P0336, P0337, and P0338 should not set.
2. Move related harnesses/connectors of the CKP sensor and verify the engine does not stumble, stall, or change engine speed.
3. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

### Circuit/System Testing

Important: If the CKP sensor lead is damaged in any way, replace the CKP sensor.

1. Ignition OFF, disconnect the harness connector at the CKP sensor.
2. Ignition ON, verify 2-3 volts is available on the signal circuit and the low reference circuit.

⇒ | If less than the specified range, test the applicable circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

⇒ | If greater than the specified range, test the applicable circuit for a short to voltage. If the circuit tests normal, replace the ECM.

3. Ignition OFF, test for 5 ohms of resistance between the ground shield circuit and ground.

⇒ | If greater than the specified range, repair the open/high resistance.

4. Disconnect the ECM connectors. Test for continuity between the following circuits:

• | The signal circuit and the low reference circuit

• | The signal circuit and the ground shield circuit

• | The low reference circuit and the ground shield circuit

• | The DMM should display OL between all circuits.

⇒ | If continuity exists between any of the circuits, repair the short between those circuits.

5. If all circuits test normal, test or replace the CKP sensor.

### Component Testing

1. Ignition OFF, disconnect the harness connector at the CKP sensor.

Important: If the CKP sensor lead is damaged in any way, replace the CKP sensor.

2. Connect a DMM between the signal circuit and the low reference circuit.
3. Test for 500-700 ohms between the signal terminal and low reference terminal.

⇒ | If the resistance is not within the specified range, replace the CKP sensor.

4. Set the DMM to the AC voltage scale.
5. While cranking the engine, test for more than 1.3 ACV between the signal circuit and low reference circuit.

⇒ | If less than the specified range, replace the CKP sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Crankshaft Position Sensor Replacement

• | Control Module References for engine control module replacement, setup, and programming