P2122

DTC P2122: Accelerator Pedal Position Sensor (main) Circuit Low Input














CIRCUIT OPERATION

- A 5-volt power supply is applied on the accelerator pedal position sensor (main) power terminal (terminal No. 1) from the ECM (terminal No. 75).

- A voltage that is according to the accelerator opening angle is sent to the ECM
(terminal No. 74) from the accelerator pedal position sensor (main) output terminal (terminal No. 3).

- The ground terminal (terminal No. 2) is grounded with ECM (terminal No. 76).

TECHNICAL DESCRIPTION

- The accelerator pedal position sensor (main) outputs voltage which corresponds to the accelerator pedal depression.

- The ECM checks whether the voltage is within a specified range.

DESCRIPTIONS OF MONITOR METHODS

Accelerator pedal position sensor (main) output voltage is out of specified range.

MONITOR EXECUTION

Continuous

MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)

- Not applicable
Sensor (The sensor below is determined to be normal)

- Not applicable

DTC SET CONDITIONS

Logic Flow Chart






Check Condition

- Ignition switch is "ON" position.
Judgement Criterion

- Accelerator pedal position sensor (main) output voltage is 0.2 volt or less for 0.3 second.

OBD-II DRIVE CYCLE PATTERN

None.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)

- Accelerator pedal position sensor failed.

- Connector damage.

- Harness damage.

- ECM failed.

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.

- MB991827: USB Cable

- MB991910: Main Harness A

STEP 1. Check harness connector C-123 at accelerator pedal position sensor and harness connector B-11 at ECM for damage.

Q. Is the harness connector in good condition?

YES Go to Step 2.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 4.
STEP 2. Check for open circuit or short circuit to ground or harness damage between accelerator pedal position sensor connector C-123 and ECM connector B-11.





(1)Disconnect the connector C-123 and B-11 measure at the harness side.
(2)Measure the resistance between connector C-123 and connector B-11.
1. Connector C-123 (terminal No. 1) and connector B-11 (terminal No. 75).

2. Connector C-123 (terminal No. 3) and connector B-11 (terminal No. 74).

- Should be less than 2 ohms.





(3)Check for the continuity between connector C-123 and ground.
3. Connector C-123 (terminal No. 1) and ground.

4. Connector C-123 (terminal No. 3) and ground.

- Not continuity.

Q. Is the harness wire in good condition?

YES Go to Step 3.

NO Repair it. Then go to Step 4.

STEP 3. Using scan tool MB991958, check data list item 11: Accelerator Pedal Position Sensor (main).





CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

(1)Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to the "ON" position.
(3)Set scan tool MB991958 to the data reading mode for item 11, Accelerator Pedal Position Sensor (main).

- Output voltage is between 0.9 and 1.1 volts when foot is released from accelerator pedal.

- Output voltage is 4.0 volts or higher when accelerator pedal is fully depressed.
(4)Turn
the ignition switch to the "LOCK" (OFF) position.

Q. Is the sensor operating properly?

YES Go to Step 4.

NO Replace the accelerator pedal position sensor. Then go to Step 4.

STEP 4. Using scan tool MB991958, read the diagnostic trouble code
(DTC).

(1)Connect scan tool MB991958 to the data link connector.

(2)Turn the ignition switch to the "ON" position.

(3)Read the DTC again.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is DTC P2122 set?

YES Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID registration procedure manual - ID codes registration judgement table [Vehicles with KOS] or ID registration procedure manual - ID codes registration judgement table [Vehicles with WCM].
NO It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.