FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Mitsubishi >> 2012 >> Eclipse Spyder L4-2.4L (4G69) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0151

P0151




DTC P0151: Cylinder 2, 3 Heated Oxygen Sensor (front) Circuit Low Voltage














CIRCUIT OPERATION

- A voltage corresponding to the oxygen concentration in the exhaust gas is sent to the ECM [M/T] or the PCM [A/T] (terminal No. 91) from the output terminal (terminal No. 4) of the cylinder 2, 3 heated oxygen sensor (front).
- Terminal No. 2 of the cylinder 2, 3 heated oxygen sensor (front) is grounded with ECM [M/T] or PCM [A/T] (terminal No. 79).
- The ECM [M/T] or the PCM [A/T] applies an offset voltage of 0.5 volt to terminal No. 2 of the cylinder 1, 4 heated oxygen sensor (front)

TECHNICAL DESCRIPTION

- The cylinder 2, 3 heated oxygen sensor (front) detects the concentration of oxygen in the exhaust gas; it converts those data to voltage, and inputs the resulting signals to the ECM [M/T] or the PCM [A/T].
- When the cylinder 2, 3 heated oxygen sensor (front) begins to deteriorate, the heated oxygen sensor signal response becomes poor.
- The ECM [M/T] or the PCM [A/T]checks for the cylinder 2, 3 heated oxygen sensor (front) output voltage.

DESCRIPTIONS OF MONITOR METHODS

Cylinder 2, 3 heated oxygen sensor (front) output voltage is under 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)

- Heated oxygen sensor heater (front) monitor
- Misfire monitor
- Fuel system monitor
Sensor (The sensor below is determined to be normal)

- Mass airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Throttle position sensor
- Accelerator pedal position sensor

DTC SET CONDITIONS

Logic Flow Chart






Check Conditions

- Heated oxygen sensor offset voltage is between 0.4 and 0.6 volt.
- Battery positive voltage is between 11 and 16.5 volts.
- 180 seconds have passed since the engine starting sequence was completed.
Judgement Criterion

- Cylinder 1, 4 heated oxygen sensor (front) output voltage is lower than 0.2 volt.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 22 Monitors, Trips, Drive Cycles and Readiness Codes.

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

- Cylinder 2, 3 heated oxygen sensor (front) failed.
- Open or shorted circuit in cylinder 2, 3 heated oxygen sensor (front) output line, or harness damage.
- Open circuit in cylinder 2, 3 heated oxygen sensor (front) ground line, or harness damage.
- Connector damage.
- ECM failed. [M/T]
- PCM failed. [A/T]

DIAGNOSIS

Required Special Tools:

- MB991958: Scan tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
- MB991316: Test Harness
- MB991923: Power Plant ECU Check Harness

STEP 1. Using scan tool MB991958, check data list item AE: Cylinder 2, 3 Heated Oxygen Sensor (front).





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)Start the engine and run at idle.
(3)Set scan tool MB991958 to the data reading mode for item AE, Cylinder 2, 3 Heated Oxygen Sensor (front).

- Warm up the engine. When the engine is revved, the output voltage should measure 0.6 to 1.0 volt.
- Warm up the engine. When the engine is idling, the output voltage should repeat 0.4 volt and 0.6 to 1.0 volt alternately.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the sensor operating properly?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

NO Go to Step 2.

STEP 2. Measure the sensor output voltage at cylinder 2, 3 heated oxygen sensor (front) connector B-35 by backprobing





(1)Do not disconnect the connector B-35.
(2)Start the engine and run at idle.





(3)Measure the voltage between terminal No. 4 and ground by backprobing.

- Warm up the engine. When the engine is 2,500 r/min, the output voltage should repeat 0.5 to 1.4 volts alternately.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the measured voltage within the specified range?

YES Go to Step 3.

NO Go to Step 7.

STEP 3. Measure the sensor output voltage at ECM [M/T] or PCM [A/T] connector B-21 by using power plant ECU check harness special tool MB991923.









(1)Disconnect all ECM [M/T] connectors or PCM [A/T] connectors.
Connect the power plant ECU check harness special tool MB991923 between the separated connectors.
(2)Start the engine and run at idle.





(3)Measure the voltage between terminal No. 91 and ground.

- Warm up the engine. When the engine is 2,500 r/min, the output voltage should repeat 0.5 to 1.4 volts alternately.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the measured voltage within the specified range?

YES Go to Step 4.

NO Go to Step 6.

STEP 4. Check harness connector B-35 at cylinder 2, 3 heated oxygen sensor (front) and harness connector B-21 at ECM [M/T] or PCM [A/T] for damage.









Q. Is the harness connector in good condition?

YES Go to Step 5.

NO Repair or replace it. Harness Connector Inspection.
Then go to Step 14.

STEP 5. Using scan tool MB991958, check data list item AE: Cylinder 2, 3 Heated Oxygen Sensor (front).





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)Start the engine and run at idle.
(3)Set scan tool MB991958 to the data reading mode for item AE, Cylinder 2, 3 Heated Oxygen Sensor (front).

- Warming up the engine. When the engine is revved, the output voltage should be 0.6 to 1.0 volt.
- Warming up the engine. When the engine is idling, the output voltage should repeat 0.4 volt and 0.6 to 1.0 volt alternately.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the sensor operating properly?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

NO Replace the ECM [M/T] or PCM [A/T]. Then go to Step 14.

STEP 6. Check harness connector B-35 at cylinder 2, 3 heated oxygen sensor (front) and harness connector B-21 at ECM [M/T] or PCM [A/T] for damage.









Q. Is the harness connector in good condition?

YES Repair harness wire between cylinder 2, 3 heated oxygen sensor (front) connector B-35 (terminal No. 4) and ECM [M/T] or PCM [A/T] connector B-21 (terminal No. 91) because of open circuit or harness damage. Then go to Step 14.

NO Repair or replace it. Harness Connector Inspection.
Then go to Step 14.

STEP 7. Check harness connector B-35 at cylinder 2, 3 heated oxygen sensor (front) for damage.





Q. Is the harness connector in good condition?

YES Go to Step 8.

NO Repair or replace it. Harness Connector Inspection.
Then go to Step 14.

STEP 8. Measure the sensor offset voltage at ECM [M/T] or PCM [A/T] connector B-20 by using power plant ECU check harness special tool MB991923.





(1)Disconnect all ECM [M/T] connectors or PCM [A/T] connectors.
Connect the power plant ECU check harness special tool MB991923 between the separated connectors.
(2)Turn the ignition switch to the "ON" position.









(3)Measure the voltage between terminal No. 79 and ground.

- Voltage should be between 0.4 and 0.6 volt.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the measured voltage between 0.4 and 0.6 volt?

YES Go to Step 10.

NO Go to Step 9.

STEP 9. Check harness connector B-20 at ECM [M/T] or PCM [A/T] for damage.





Q. Is the harness connector in good condition?

YES Repair harness wire between cylinder 2, 3 heated oxygen sensor (front) connector B-35 (terminal No. 2) and ECM [M/T] or PCM [A/T] connector B-20 (terminal No. 79) because of open circuit or harness damage. Then go to Step 14.

NO Repair or replace it. Harness Connector Inspection.
Then go to Step 14.

STEP 10. Check harness connector B-20 at ECM [M/T] or PCM [A/T] for damage.





Q. Is the harness connector in good condition?

YES Go to Step 11.

NO Repair or replace it. Then go to Step 14.

STEP 11. Check for harness damage between cylinder 2, 3 heated oxygen sensor (front) connector B-35 (terminal No. 2) and ECM [M/T] or PCM [A/T] connector B-20 (terminal No. 79).









Q. Is the harness wire in good condition?

YES Go to Step 12.

NO Repair it. Then go to Step 14.

STEP 12. Check for short circuit to ground and harness damage between cylinder 2, 3 heated oxygen sensor (front) connector B-35 (terminal No. 4) and ECM [M/T] or PCM [A/T] connector B-21 (terminal No. 91).









Q. Is the harness wire in good condition?

YES Go to Step 13.

NO Repair it. Then go to Step 14.

STEP 13. Check the cylinder 2, 3 heated oxygen sensor (front).





(1)Disconnect the cylinder 2, 3 heated oxygen sensor (front) connector B-35 and connect test harness special tool MB991316, to the connector on the cylinder 2, 3 heated oxygen sensor (front) side.
(2)Warm up the engine until engine coolant temperature reaches 80°C (176°F) or higher.
(3)Rev the engine for 5 minutes or more with the engine speed of 4,500 r/min.





(4)Connect a digital voltage meter between terminal No. 2 (black clip) and terminal No. 4 (white clip).
(5)While repeatedly revving the engine, measure the cylinder 2, 3 heated oxygen sensor (front) output voltage.
Standard value: 0.6 - 1.0 V

CAUTION:

- Be very careful when connecting the jumper wires; incorrect connection can damage the heated oxygen sensor.
- Be careful the heater can be damaged if a voltage beyond 8 volts is applied to the heated oxygen sensor heater.

NOTE:
If the temperature of sensing area does not reach the high temperature [of approximately 400°C (752°F) or more]
even through the heated oxygen sensor is normal, the output voltage would be possibly low in spite of the rich air-fuel ratio. Therefore, if the output voltage is low, use a jumper wire to connect the terminal No. 1 (red clip) and the terminal No. 3 (blue clip) of the heated oxygen sensor with the positive terminal and the negative terminal of 8 volts power supply respectively, then check again.

Q. Is the measured voltage between 0.6 and 1.0 volt?

YES Replace the ECM or the PCM. When the ECM or the PCM is replaced, register the encrypted code. Immobilizer System.
Then go to Step 14.

NO Replace the cylinder 2, 3 heated oxygen sensor (front). Then go to Step 14.

STEP 14. Test the OBD-II drive cycle.

(1)Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 22 Monitors, Trips, Drive Cycles and Readiness Codes.

(2)Check the diagnostic trouble code (DTC).

Q. Is DTC P0151 set?

YES Retry the troubleshooting.
NO The inspection is complete.
pro multis Credits:Operation CHARM About Operation CHARM