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2008 - MX-5 - Engine

DTC P0340 [LF]



DTC P0340

CMP sensor circuit problem

DETECTION CONDITION

  • The PCM monitors the input voltage from the CMP sensor when the engine is running. If the PCM does not receive the input voltage from the CMP sensor while the PCM receives the input signal from the CKP sensor, the PCM determines that the CMP sensor circuit has a malfunction.

  • If a malfunction is detected in the input pulse pattern from the CMP sensor.

    Diagnostic support note
  • This is a continuous monitor (CCM).

  • The MIL illuminates if the PCM detects the above malfunction condition during the first drive cycle.

  • PENDING CODE is available if the PCM detects the above malfunction condition.

  • FREEZE FRAME DATA is available.

  • The DTC is stored in the PCM memory.

POSSIBLE CAUSE

  • CMP sensor malfunction

  • Connector or terminal malfunction

  • CMP sensor is dirty

  • Short to power supply in wiring harness between CMP sensor terminal B and PCM terminal 2S

  • Short to power supply in wiring harness between CMP sensor terminal A and PCM terminal 2P

  • Short to ground circuit in wiring harness between CMP sensor terminal C and PCM terminal 2AM

  • Short to ground circuit in wiring harness between CMP sensor terminal B and PCM terminal 2S

  • Open circuit in wiring harness between CMP sensor terminal A and PCM terminal 2P

  • Open circuit in wiring harness between CMP sensor terminal B and PCM terminal 2S

  • Open circuit in wiring harness between CMP sensor terminal C and PCM terminal 2AM

  • Both CMP sensor wires are shorted to each other

  • CMP sensor pulse wheel malfunction

  • CMP sensor misinstallation

  • Timing chain misinstallation

  • Loose timing chain or improper valve timing

  • Loose camshaft sprocket lock bolt

  • Loose crankshaft pulley lock bolt

  • PCM malfunction


Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
  • Has FREEZE FRAME DATA been recorded?

Yes

Go to the next step.

No

Record the FREEZE FRAME DATA on the repair order, then go to the next step.

2

VERIFY RELATED REPAIR INFORMATION AVAILABILITY
  • Verify related Service Bulletins and/or on-line repair information availability.

  • Is any related repair information available?

Yes

Perform repair or diagnosis according to the available repair information.

  • If the vehicle is not repaired, go to the next step.

No

Go to the next step.

3

VERIFY CMP SENSOR VOLTAGE
  • Disconnect the CMP sensor connector.

  • Connect a voltmeter between CMP sensor terminals B and C (sensor-side).

  • Inspect the voltage in AC range while cranking the engine.

  • Is there any voltage?

Yes

Go to the next step.

No

Go to step 10.

4

INSPECT CMP SENSOR CONNECTOR FOR POOR CONNECTION
  • Verify that the CMP sensor connector is connected securely.

  • Is the connector normal?

Yes

Go to the next step.

No

Reconnect the connector, then go to Step 15.

5

INSPECT CMP SENSOR CIRCUIT FOR SHORT TO POWER SUPPLY
  • Turn the ignition switch off.

  • Disconnect the CMP sensor connector.

  • Turn ignition switch to the ON position (Engine off)

  • Measure the voltage between the following terminals:

    • CMP sensor terminal B (wiring harness-side) and body ground

    • CMP sensor terminal A (wiring harness-side) and body ground

  • Is the voltage B+?

Yes

Repair or replace the suspected wiring harness, then go to Step 15.

No

Go to the next step.

6

INSPECT CMP SENSOR CIRCUIT FOR SHORT TO GROUND
  • Inspect for continuity between the following terminal and body ground:

    • CMP sensor terminal B (wiring harness-side)

    • CMP sensor terminal C (wiring harness-side)

  • Is there continuity?

Yes

Repair or replace the suspected wiring harness, then go to Step 15.

No

Go to the next step.

7

INSPECT CMP SENSOR CIRCUITS FOR SHORT CIRCUIT
  • Inspect for continuity between CMP sensor terminals B and C (wiring harness-side).

  • Is there continuity?

Yes

Repair or replace the suspected wiring harness, then go to Step 15.

No

Go to the next step.

8

INSPECT PCM CONNECTOR FOR POOR CONNECTION
  • Disconnect the PCM connector.

  • Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.).

  • Is there any malfunction?

Yes

Repair the terminal, then go to Step 15.

No

Go to the next step.

9

INSPECT CMP SENSOR CIRCUIT FOR OPEN CIRCUIT
  • Inspect for continuity between the following circuits:

    • CMP sensor terminal A (wiring harness-side) and PCM terminal 2P (wiring harness-side)

    • CMP sensor terminal B (wiring harness-side) and PCM terminal 2S (wiring harness-side)

    • CMP sensor terminal C (wiring harness-side) and PCM terminal 2AM (wiring harness-side)

  • Is there continuity?

Yes

Go to Step 11.

No

Repair or replace the suspected wiring harness, then go to Step 15.

10

INSPECT CMP SENSOR

Yes

Go to the Step 15.

No

Replace the CMP sensor and go to Step 15.

(See CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [LF].)

11

VERIFY CMP SENSOR INSTALLATION

Yes

Go to the next step.

No

Reinstall the CMP sensor and go to Step 15.

12

VERIFY VALVE TIMING MECHANISM INSTALLATION
  • Verify the valve timing mechanism installation for the following parts:

    • Timing chain misinstallation

    • Loose camshaft sprocket lock bolt

    • Loose crankshaft pulley lock bolt

  • Is the valve timing mechanism installed correctly?

Yes

Go to the next step.

No

Reinstall the following parts and go to Step 15.

  • Timing chain

  • Camshaft sprocket

  • Crankshaft pulley

13

INSPECT STOPPER PIN MECHANISM

Yes

Go to the next step.

No

Replace the variable valve timing actuator, then go to Step 15.

(See VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [LF].)

14

INSPECT ROTOR POSITION

Yes

VARIABLE VALVE TIMING MECHANISM NORMAL

NOTE:

  • This DTC is detected as an intermittent concern.

  • The intermittent concern might be removed by cleaning the variable valve timing mode control function.

Go to the next step.

No

Replace the variable valve timing actuator, then go to the next step.

(See VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [LF].)

15

VERIFY TROUBLESHOOTING OF DTC P0340 COMPLETED
  • Make sure to reconnect all disconnected connectors.

  • Turn ignition switch to the ON position (Engine off).

  • Clear the DTC from the PCM memory using the M-MDS.

  • Start the engine.

  • Access the MAF PID using the M-MDS.

    NOTE:

    • The MAF PID should indicate 1.95 g/s {0.25 lb/min.} or above during this test

  • Is same DTC present?

Yes

Replace the PCM, then go to the next step.

(See PCM REMOVAL/INSTALLATION [LF].)

No

Go to the next step.

16

VERIFY AFTER REPAIR PROCEDURE

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [LF].)

No

Troubleshooting completed.




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