DTC P0340 [L8, LF, L3]

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 circuit has a malfunction. Diagnostic support note • This is a continuous monitor (CCM). • MIL illuminates if the PCM detects the above malfunction condition during first drive cycle. • PENDING CODE is available if the PCM detects the above malfunction condition. • FREEZE FRAME DATA is available. • DTCs are stored in the PCM memory.
POSSIBLE CAUSE	• CMP sensor malfunction • Connector or terminal malfunction • CMP sensor is dirty • Short to the power circuit between CMP sensor terminal B and PCM terminal 2S • Short to ground circuit between CMP sensor terminal C and PCM terminal 2AM • Short to ground circuit between CMP sensor terminal B and PCM terminal 2S • Open circuit between CMP sensor terminal A and body ground • Open circuit between CMP sensor terminal B and PCM terminal 2S • Open circuit between CMP sensor terminal C and PCM terminal 2AM • Both CMP sensor wires are shorted to each other • CKP sensor pulse wheel malfunction • CKP sensor misinstallation • Timing chain misinstallation • Loose timing chain or improper valve timing • Loose camshaft sprocket lock bolt • Loose crankshaft pulley lock bolt • PCM malfunction

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 circuit has a malfunction.

Diagnostic support note

• This is a continuous monitor (CCM).

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

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

• FREEZE FRAME DATA is available.

• DTCs are stored in the PCM memory.

POSSIBLE CAUSE

• CMP sensor malfunction

• Connector or terminal malfunction

• CMP sensor is dirty

• Short to the power circuit between CMP sensor terminal B and PCM terminal 2S

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

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

• Open circuit between CMP sensor terminal A and body ground

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

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

• Both CMP sensor wires are shorted to each other

• CKP sensor pulse wheel malfunction

• CKP sensor misinstallation

• Timing chain misinstallation

• Loose timing chain or improper valve timing

• Loose camshaft sprocket lock bolt

• Loose crankshaft pulley lock bolt

• PCM malfunction

STEP	INSPECTION	ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
No	Record the FREEZE FRAME on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available?	Yes	Perform repair or diagnosis according to the available Service information. If the vehicle is not repaired, go to the next step.
No	Go to the next step.
3	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 14.
4	INSPECT CMP CIRCUIT FOR SHORT TO POWER • Turn the ignition switch off. • Disconnect the CMP sensor connector. • Turn ignition switch to the ON position (Engine off) • Measure voltage between the CMP sensor connector terminal B (wiring harness-side) and body ground. • Is the voltage B+?	Yes	Repair or replace the suspected wiring harness, then go to Step 14.
No	Go to the next step.
5	INSPECT CMP CIRCUIT FOR SHORT TO GROUND • Inspect for continuity between the following terminal and body ground: ― CMP sensor connector terminal B (wiring harness-side) ― CMP sensor connector terminal C (wiring harness-side) • Is there continuity?	Yes	Repair or replace the suspected wiring harness, then go to Step 14.
No	Go to the next step.
6	INSPECT CMP CIRCUITS FOR SHORT CIRCUIT • Inspect for continuity between CMP sensor connector terminals B and C (wiring harness-side). • Is there continuity?	Yes	Repair or replace the suspected wiring harness, then go to Step 14.
No	Go to the next step.
7	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 14.
No	Go to the next step.
8	INSPECT CMP CIRCUIT FOR OPEN CIRCUIT • Inspect for continuity between the following circuits: ― CMP sensor terminal A (wiring harness-side) and body ground ― 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 the next step.
No	Repair or replace the suspected wiring harness, then go to Step 14.
9	INSPECT CMP SENSOR • Turn the ignition switch off. • Perform the CMP sensor inspection. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [L8, LF, L3].) • Is the CMP sensor normal?	Yes	Go to the next step.
No	Replace the CMP sensor and go to Step 14.
10	VERIFY CKP SENSOR INSTALLATION • Verify the CKP sensor installation. (See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [L8, LF, L3].) • Is the CKP sensor installed correctly?	Yes	Go to the next step.
No	Reinstall the CKP sensor and go to Step 14.
11	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 14. • Timing chain • Camshaft sprocket • Crankshaft pulley
12	INSPECT STOPPER PIN MECHANISM (LF, L3) • Remove the timing chain. • Inspect the stopper pin. (See VARIABLE VALVE TIMING ACTUATOR INSPECTION [LF, L3].) • Is the stopper pin mechanism normal?	Yes	Go to the next step.
No	Replace the variable valve timing actuator, then go to Step 14.
13	INSPECT ROTOR POSITION (LF, L3) • Remove the variable valve timing actuator. (See VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [LF, L3]) • Is the rotor position at the maximum valve timing retard?	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.
14	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 WDS or equivalent. • Start the engine. • Access the MAF PID using the WDS or equivalent. 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 [L8, LF, L3].)
No	Go to the next step.
15	VERIFY AFTER REPAIR PROCEDURE • Perform the “After Repair Procedure”. (See AFTER REPAIR PROCEDURE [L8, LF, L3].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [L8, LF, L3].)
No	Troubleshooting completed.

STEP

INSPECTION

ACTION

VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAS BEEN RECORDED

• Has FREEZE FRAME DATA been recorded?

Yes

Go to the next step.

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

VERIFY RELATED REPAIR INFORMATION AVAILABILITY

• Verify related Service Information availability.

• Is any related Service Information available?

Yes

Perform repair or diagnosis according to the available Service information.

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

Go to the next step.

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.

Reconnect the connector, then go to Step 14.

INSPECT CMP CIRCUIT FOR SHORT TO POWER

• Turn the ignition switch off.

• Disconnect the CMP sensor connector.

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

• Measure voltage between the CMP sensor connector terminal B (wiring harness-side) and body ground.

• Is the voltage B+?

Yes

Repair or replace the suspected wiring harness, then go to Step 14.

Go to the next step.

INSPECT CMP CIRCUIT FOR SHORT TO GROUND

• Inspect for continuity between the following terminal and body ground:

― CMP sensor connector terminal B (wiring harness-side)

― CMP sensor connector terminal C (wiring harness-side)

• Is there continuity?

Yes

Repair or replace the suspected wiring harness, then go to Step 14.

Go to the next step.

INSPECT CMP CIRCUITS FOR SHORT CIRCUIT

• Inspect for continuity between CMP sensor connector terminals B and C (wiring harness-side).

• Is there continuity?

Yes

Repair or replace the suspected wiring harness, then go to Step 14.

Go to the next step.

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 14.

Go to the next step.

INSPECT CMP CIRCUIT FOR OPEN CIRCUIT

• Inspect for continuity between the following circuits:

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

― 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 the next step.

Repair or replace the suspected wiring harness, then go to Step 14.

INSPECT CMP SENSOR

• Turn the ignition switch off.

• Perform the CMP sensor inspection.

(See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [L8, LF, L3].)

• Is the CMP sensor normal?

Yes

Go to the next step.

Replace the CMP sensor and go to Step 14.

VERIFY CKP SENSOR INSTALLATION

• Verify the CKP sensor installation.

(See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [L8, LF, L3].)

• Is the CKP sensor installed correctly?

Yes

Go to the next step.

Reinstall the CKP sensor and go to Step 14.

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.

Reinstall the following parts and go to Step 14.

• Timing chain

• Camshaft sprocket

• Crankshaft pulley

INSPECT STOPPER PIN MECHANISM (LF, L3)

• Remove the timing chain.

• Inspect the stopper pin.

(See VARIABLE VALVE TIMING ACTUATOR INSPECTION [LF, L3].)

• Is the stopper pin mechanism normal?

Yes

Go to the next step.

Replace the variable valve timing actuator, then go to Step 14.

INSPECT ROTOR POSITION (LF, L3)

• Remove the variable valve timing actuator.

(See VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [LF, L3])

• Is the rotor position at the maximum valve timing retard?

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.

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

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 WDS or equivalent.

• Start the engine.

• Access the MAF PID using the WDS or equivalent.

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 [L8, LF, L3].)

Go to the next step.

VERIFY AFTER REPAIR PROCEDURE

• Perform the “After Repair Procedure”.

(See AFTER REPAIR PROCEDURE [L8, LF, L3].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [L8, LF, L3].)

Troubleshooting completed.

Mazdamanuals.com