DTC P0120 [WL-3]

id0102b8954300

DTC P0120

APP sensor circuit malfunction
DETECTION CONDITION
•  The PCM monitors the APP sensor signal at PCM terminal 1R. If the PCM detects either of the following conditions, the PCM determines that the APP sensor circuit has a malfunction.
―  Input voltage at PCM terminal 1R is below 0.29 V.
―  Input voltage at PCM terminal 1R is above 4.80 V.
―  Input voltage at PCM terminal 1R is above 1.35 V with idle switch ON.
•  The PCM monitors the difference in voltage between the main circuit and the monitor circuit of the APP sensor. If the difference in voltage between PCM terminal 1R and 2C is above 0.90 V, the PCM determines that the APP sensor has a malfunction.
POSSIBLE CAUSE
•  APP sensor malfunction
•  Poor connection at APP sensor or PCM connector
•  Open circuit between APP sensor terminal B and PCM terminal 1R
•  Short to ground circuit between APP sensor terminal B and PCM terminal 1R
•  Open circuit between APP sensor terminal A and PCM terminal 1A
•  Short to ground circuit between APP sensor terminal A and PCM terminal 1A
•  Open circuit between APP sensor terminal C and PCM terminal 2C
•  Short to ground circuit between APP sensor terminal C and PCM terminal 2C
•  PCM malfunction
•  Open circuit between APP sensor terminal D and PCM terminal 1B
•  Short to reference voltage (Vref) supply circuit between APP sensor terminal B and PCM terminal 1R
•  Short to reference voltage (Vref) supply circuit between APP sensor terminal C and PCM terminal 2C
•  Electrical corrosion in APP signal circuit
•  Voltage drops in reference voltage (Vref) supply circuit
•  Idle switch malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY RELATED REPAIR INFORMATION AVAILABILITY
•  Verify related service 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.
2
VERIFY CURRENT SIGNAL STATUS: IS CONCERN INTERMITTENT OR CONSTANT?
•  Clear the DTC.
•  Start the engine.
•  Is the same DTC present?
Yes
Go to the next step.
No
Intermittent concern exists.
Perform the “INTERMITTENT CONCERN TROUBLESHOOTING”.
(See INTERMITTENT CONCERN TROUBLESHOOTING [WL-3].)
3
INSPECT APP SENSOR CONNECTOR FOR POOR CONNECTION
•  Turn the engine switch to the off position.
•  Disconnect the APP sensor connector.
•  Check for poor connection (damaged,
pulled-out pins, corrosion, etc.).
•  Is there a malfunction?
Yes
Repair or replace the connector, then go to the next step.
No
Go to the next step.
4
INSPECT APP SENSOR TERMINAL
•  Check for a bent terminal of APP sensor terminals (part-side).
•  Is there a malfunction?
Yes
Repair or replace the terminal, then go to Step 11.
No
Go to the next step.
5
CHECK TERMINAL VOLTAGE AT APP SENSOR
•  Check the voltage at APP sensor terminals A, B and C (part-side).
•  Is the voltage approx. 5 V?
Yes
Go to the next step.
No
•  If the voltage is approx. B+, repair or replace the appropriate wiring harnesses.
Then, go to Step 11.
•  If the voltage is approx. 0V, go to Step 8
6
VERIFY APP SENSOR CIRCUIT FOR SHORT TO REFERENCE VOLTAGE (VREF) SUPPLY CIRCUIT
•  Check for continuity between following terminals:
―  APP sensor terminals A and B (part-side)
―  APP sensor terminals A and C (part-side)
•  Is there continuity?
Yes
Repair or replace the appropriate wiring harnesses, then go to Step 11.
No
Go to the next step.
7
VERIFY APP SENSOR CIRCUIT FOR SHORT TO GROUND
•  Check for continuity between following terminals:
―  APP sensor terminal A (part-side) and body ground
―  APP sensor terminal B (part-side) and body ground
―  APP sensor terminal C (part-side) and body ground
•  Is there continuity?
Yes
Repair or replace the appropriate wiring harnesses, then go to Step 11.
No
Go to the next step.
8
INSPECT PCM CONNECTOR FOR POOR CONNECTION
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there a malfunction?
Yes
Repair or replace the terminal, then go to Step 11.
No
Go to the next step.
9
VERIFY APP SENSOR MAIN CIRCUIT,MONITOR CIRCUIT AND GROUND CIRCUIT FOR OPEN CIRCUIT
•  Check for continuity between following terminals:
―  APP sensor terminal A (wiring harness-side) and PCM terminal 1A
―  APP sensor terminal B (wiring harness-side) and PCM terminal 1R
―  APP sensor terminal C (wiring harness-side) and PCM terminal 2C
―  APP sensor terminal D (wiring harness-side) and PCM terminal 1B
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the appropriate wiring harnesses, then go to Step 11.
10
INSPECT APP SENSOR
•  Make sure to reconnect all disconnected connectors.
•  Inspect the APP sensor.
•  Is it normal?
Yes
Go to the next step.
No
Replace the APP sensor, then go to Step 11.
11
VERIFY TROUBLESHOOTING OF DTC P0120 COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Turn the engine switch to the ON position (Engine off).
•  Connect the M-MDS.
•  Clear the DTCs from the PCM memory.
•  Start the engine.
•  Is the same DTC present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
12
VERIFY AFTER REPAIR PROCEDURE
•  Perform “AFTER REPAIR PROCEDURE”.
•  Is there any DTC present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [WL-3].)
No
Troubleshooting completed.