• | 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. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
CMP 5-Volt Reference | P0642 | P0340 | P0340 | P0643 | P0341 |
CMP Sensor Signal | P0340 | P0340 | P0340 | P0340 | P0341 |
CMP Low Reference | -- | P0340 | P0340 | -- | P0341 |
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
---|---|---|---|---|
Operating Conditions: Engine running | ||||
CMP 5-Volt Reference Voltage | Yes | No | No | Yes |
CMP Sensor Signal | Yes | No | No | No |
CMP Low Reference | Yes | -- | No | -- |
The hall effect camshaft position (CMP) sensor produces 3 ON/OFF pulses for each revolution of the camshaft. The CMP output is pulse width encoded. The engine control module (ECM) uses the CMP and crankshaft position (CKP) output pulses to determine the engine speed and position. The CMP is connected directly to the ECM by the following circuits:
• | The 5-volt reference circuit |
• | The low reference circuit |
• | The CMP sensor signal circuit |
• | The ignition is ON. |
• | The engine is turning faster than 50 RPM. |
• | DTC P0340 runs continuously when the above conditions are met. |
• | DTCs P0335, P0336, P0642, or P0643 are not set. |
The ECM does not see a CMP sensor signal for more than 2 seconds.
DTC P0340 is a Type A DTC.
DTC P0340 is a Type A DTC.
If the CMP sensor signal is lost while running, the engine will operate normally. If the CMP sensor signal is not present on start-up, the engine will not start.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
J 38522 Variable Signal Generator
⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If less that the specified range, test the 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If the 5-Volt Reference 1 Circuit Status parameter does not display OK, test the signal circuit for a short to 5-volt reference. If the circuit tests normal, replace the ECM. |
⇒ | If the parameter does not display YES, replace the ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |