P0157

M : DTC P0057, P0058, P0157, P0158, P0160. LH Catalyst Monitor.

M1 : CHECK THE POWER SUPPLY CIRCUIT TO THE LH CATALYST MONITOR HEATER
1. Turn the ignition switch to the OFF position.
2. Disconnect the LH catalyst monitor sensor electrical connector PI13.
3. Turn the ignition switch to the ON position.
4. Measure the voltage between PI13, pin 1 (WR) and GROUND.

Is the voltage less than 10 volts?

Yes
Repair the circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

No
Goto M2

M2 : CHECK THE GROUND SUPPLY CIRCUIT TO THE LH CATALYST MONITOR HEATER FOR CONTINUITY
1. Turn the ignition switch to the OFF position.
2. Disconnect the PCM electrical connector PI01.
3. Measure the resistance between PI13, pin 2 (RW) and PI01, pin 93 (RW)

Is the resistance less than 5 ohms?

Yes
Goto M4

No
Repair the circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

M3 : CHECK THE LH CATALYST MONITOR HEATER RESISTANCE
1. Measure the resistance between pins 1 and 2 of the LH Catalyst Monitor heater.

Is the resistance 5.0 ohms?

Yes
Goto P4. P0051

No
Install a new LH Catalyst Monitor Sensor. CLEAR the DTCs. TEST the system for normal operation.

M4 : CHECK THE GROUND SUPPLY CIRCUIT TO THE LH CATALYST MONITOR HEATER FOR SHORT TO GROUND
1. Measure the resistance between PI13, pin 2 (RW) and GROUND.

Is the resistance less than 10,000 ohms?

Yes
Repair the short circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

No
Goto M5

M5 : CHECK THE GROUND SUPPLY CIRCUIT TO THE LH CATALYST MONITOR HEATER FOR SHORT TO BATTERY
1. Connect the PCM electrical connector, PI01.
2. Turn the ignition switch to the ON position.
3. Check for a voltage at PI13, pin2 (RW)

Is the voltage greater than 5 volts?

Yes
Repair the short circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

No
Goto M6

M6 : CHECK THE CONSTANT CIRCUIT OF THE LH CATALYST MONITOR SENSOR FOR OPEN CIRCUIT
1. Disconnect the LH catalyst monitor sensor electrical connector, PI13.
2. Disconnect the PCM electrical connector, PI01.
3. Measure the resistance between PI13, pin 3 (B) and PI01, pin 130 (BW)

Is the resistance less than 5 ohms?

Yes
Goto M7

No
Repair the circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

M7 : CHECK THE CONSTANT CIRCUIT OF THE LH CATALYST MONITOR SENSOR FOR SHORT TO GROUND
1. Measure the resistance between PI01, pin 130 (BW) and GROUND.

Is the resistance less than 10,000 ohms?

Yes
Repair the short circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

No
Goto M8

M8 : CHECK THE CONSTANT CIRCUIT OF THE LH CATALYST MONITOR SENSOR FOR SHORT TO BATTERY
1. Connect the PCM electrical connector, PI01.
2. Turn the ignition switch to the ON position.
3. Measure the voltage between PI13, pin 3 (B) and GROUND.

Is the voltage greater than 5 volts?

Yes
Repair the short circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

No
Goto M9

M9 : CHECK THE VARIABLE CIRCUIT OF THE LH CATALYST MONITOR SENSOR FOR OPEN CIRCUIT
1. Disconnect the LH catalyst monitor sensor electrical connector PI13.
2. Disconnect the PCM electrical connector, PI01.
3. Measure the resistance between PI01, pin 129 (N) and PI13, pin 4 (N)

Is the resistance less than 5 ohms?

Yes
Goto M10

No
Repair the circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

M10 : CHECK THE VARIABLE CIRCUIT OF THE LH CATALYST MONITOR SENSOR FOR SHORT TO GROUND
1. Measure the resistance between PI13, pin 4 (N) and GROUND.

Is the resistance less than 10,000 ohms?

Yes
Repair the short circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

No
Goto M11

M11 : CHECK THE VARIABLE CIRCUIT OF THE LH CATALYST MONITOR SENSOR FOR SHORT TO BATTERY
1. Connect the PCM electrical connector PI01.
2. Turn the ignition switch to the ON position.
3. Measure the voltage between PI13, pin 4 (N) and GROUND.

Is the voltage greater than 5 volts?

Yes
Repair the short circuit. For additional information, refer to the wiring diagrams. CLEAR the DTCs. TEST the system for normal operation.

No
Install a new LH Catalyst monitor sensor. CLEAR the DTCs. TEST the system for normal operation. If the DTC is repeated, INSTALL a new PCM.