P0151

G : DTC, P0151, P0152, P0155

G1 : CHECK THE VOLTAGE AND SIGNAL GROUND SUPPLY TO THE OXYGEN SENSOR
1. Switch the ignition switch to the OFF position.
2. Raise and support the vehicle.
3. Disconnect the left hand oxygen sensor electrical connector PI7.
4. Switch the ignition switch to the RUN position.
5. Measure the voltage between the left hand oxygen sensor electrical connector PI7 pin 1, and pin 3.

Is the voltage greater than 10.5 volts?

Yes
Goto G3

No
Goto G2

G2 : CHECK THE OXYGEN SENSOR VOLTAGE SUPPLY CIRCUIT
1. Measure the voltage between the left hand oxygen sensor electrical connector PI7 pin 1, (GU) and ground.

Is the voltage greater than 10.5 volts?

Yes
REPAIR the circuit between the left hand oxygen sensor electrical connector PI7 pin 2, (NR) and the powertrain electrical connector PI1 pin 8, (N). CLEAR DTC. TEST the system for normal operation.

No
REPAIR the circuit between the left hand oxygen sensor electrical connector PI7 pin 1, (GU) and the spliced joint PIS7. CLEAR DTC. TEST the system for normal operation.

G3 : CHECK THE OXYGEN SENSOR HEATER CONTINUITY
1. Switch the ignition switch to the OFF position.
2. Measure the resistance between the oxygen sensor electrical connector PI7 pin 1, (GU) and pin 2 (NR).

Is the resistance between 3 and 10 ohms?

Yes
Goto G4

No
INSTALL a new oxygen sensor. CLEAR DTC. TEST the system for normal operation.

G4 : CHECK THE OXYGEN SENSOR FOR FAILURE
1. Connect the oxygen sensor electrical connector PI7.
2. RUN the engine until the oxygen sensor has warmed up and maintain a speed of approximately 2500 rpm.
3. Disconnect the oxygen sensor electrical connector PI7.
4. Measure the voltage between the oxygen sensor electrical connector PI7 pin 3, (NR) and pin 4 (WR).

Is the voltage between 600mV and 1.0 Volt?

Yes
Goto G5

No
INSTALL a new oxygen sensor. CLEAR DTC. TEST the system for normal operation.

G5: CHECK THE OXYGEN SENSOR FOR FAILURE
1. Connect the oxygen sensor electrical connector PI7.
2. REDUCE the engine speed to idle.
3. Disconnect the oxygen sensor electrical connector PI7.
4. Measure the voltage between the oxygen sensor electrical connector PI7 pin 3, (NR) and pin 4 (WR).

Has the voltage dropped to less than 400 mV?

Yes
Go to G6

No
INSTALL a new oxygen sensor. CLEAR DTC. TEST the system for normal operation.

G6: CHECK THE OXYGEN SENSOR FOR FAILURE
1. Connect the oxygen sensor electrical connector PI7.
2. INCREASE the engine speed to approximately 2500 rpm.
3. Disconnect the oxygen sensor electrical connector PI7.

Has the voltage increased to between 600 mV to 1.0 Volt?

Yes
Go to G7

No
INSTALL a new oxygen sensor. CLEAR DTC. TEST the system for normal operation.

G7: CHECK THE HEATED OXYGEN SENSOR FOR SHORT TO GROUND
1. Switch the ignition switch to the OFF position.
2. Disconnect the oxygen sensor electrical connector PI7.
3. Measure the resistance between the oxygen sensor electrical connector PI7 pin 1, (GU) and the oxygen sensor body, and between the oxygen sensor electrical connector PI7 pin 3, (NR) and the oxygen sensor body.

Is the resistance greater than 10 M ohms?

Yes
Go to G8

No
INSTALL a new oxygen sensor. CLEAR DTC. TEST the system for normal operation.

G8: CHECK THE OXYGEN SENSOR SIGNAL GROUND CIRCUIT FOR OPEN
1. Measure the resistance between the oxygen sensor electrical connector PI7 pin 3, (NR) and ground.

Is the resistance greater than 10,000 ohms?

Yes
REPAIR the circuit between the oxygen sensor electrical connector PI7 pin 3, (NR) and the spliced joint P1S6. CLEAR DTC. TEST the system for normal operation.

No
Go to G9

G9: CHECK THE OXYGEN SENSOR INPUT CIRCUIT FOR OPEN
1. Remove the powertrain control module (PCM).
2. Measure the resistance between the oxygen sensor electrical connector PI7 pin 4, (WR) and the powertrain control module electrical connector PI1 pin 44, (WR).

Is the resistance greater than 10,000 ohms?

Yes
REPAIR the circuit between the oxygen sensor electrical connector PI7 pin 4, (WR) and the powertrain control module electrical connector PI1 pin 44, (WR). CLEAR DTC. TEST the system for normal operation.

No
Go to G10

G10: CHECK THE OXYGEN SENSOR CIRCUIT FOR SHORT TO GROUND
1. Measure the resistance between the oxygen sensor electrical connector PI7 pin 4, (WR) and ground.

Is the resistance less than 10,000 ohms?

Yes
REPAIR the signal ground circuit between the oxygen sensor electrical connector PI7 pin 4, (WR) and the powertrain control module electrical connector PI1 pin 44, (WR). INSTALL the powertrain control module (PCM). CLEAR DTC. TEST the system for normal operation.

No
Go to G11

G11: CHECK THE OXYGEN SENSOR HEATER CIRCUIT FOR OPEN
1. Measure the resistance between the oxygen sensor electrical connector PI7 pin 2, (NR) and the powertrain control module electrical connector PI1 pin 8, (NR).

Is the resistance greater than 10,000 ohms?

Yes
REPAIR the circuit between the oxygen sensor electrical connector PI7 pin 2, (NR) and the powertrain control module electrical connector PI1 pin 8, (NR). INSTALL the powertrain control module (PCM). CLEAR DTC. TEST the system for normal operation.

No
Go to G12

G12 : CHECK THE OXYGEN SENSOR HEATER CIRCUIT FOR SHORT TO GROUND
1. Measure the resistance between the oxygen sensor electrical connector PI7 pin 2, (BU) and ground.

Is the resistance less than 10,000 ohms?

Yes
REPAIR the output circuit between the oxygen sensor electrical connector PI7 pin 2, (NR) and the powertrain control module electrical connector PI1 pin 8, (NR). INSTALL the powertrain control module (PCM). CLEAR DTC. TEST the system for normal operation.

No
Go to G13

G13 : CHECK THE OXYGEN SENSOR SIGNAL GROUND CIRCUIT FOR SHORT TO GROUND
1. Disconnect both heated exhaust gas oxygen (HEGO) sensor electrical connectors PI6, PI7.
2. Disconnect the engine oil temperature sensor electrical connector PI12.
3. Disconnect the engine fuel temperature sensor electrical connector IL9.
4. Disconnect the cylinder head temperature sensor electrical connector PI13.
5. Disconnect both camshaft position sensor electrical connectors PI10, PI11.
6. Disconnect the injection pressure sensor electrical connector PI15.
7. Disconnect the throttle position sensor electrical connector PI16.
8. Measure the resistance between the oxygen sensor electrical connector PI7 pin 3, (NR) and ground.

Is the resistance less than 10,000 ohms?

Yes
REPAIR the signal ground circuit between the oxygen sensor electrical connector PI7 pin 3, (NR) and the spliced joint PIS6. INSTALL the powertrain control module (PCM). CLEAR DTC. TEST the system for normal operation.

No
INSTALL a new powertrain control module (PCM). CLEAR DTC. TEST the system for normal operation.