P0140

K : DTC P0037, P0038, P0137, P0138, P0140. RH Catalyst Monitor.

K1 : CHECK THE POWER SUPPLY CIRCUIT TO THE RH CATALYST MONITOR HEATER
1. Turn the ignition switch to the OFF position.
2. Disconnect the RH catalyst monitor sensor electrical connector PI11.
3. Turn the ignition switch to the ON position.
4. Measure the voltage between PI11, pin 1 (WG) 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.
This circuit includes the power distribution fuse box and EMS control relay.

No
Goto K2

K2 : CHECK THE GROUND SUPPLY CIRCUIT TO THE RH 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 PI11, pin 2 (UY) and PI01, pin 92 (UY)

Is the resistance less than 5 ohms?

Yes
Goto K3

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

K3 : CHECK THE RH CATALYST MONITOR HEATER RESISTANCE
1. Measure the resistance between pins 1 and 2 of the RH Catalyst Monitor heater.

Is the resistance 5.0 ohms?

Yes
Goto K4

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

K4 : CHECK THE GROUND SUPPLY CIRCUIT TO THE RH CATALYST MONITOR HEATER FOR SHORT TO GROUND
1. Measure the resistance between PI11, pin 2 (UY) 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 K5

K5 : CHECK THE GROUND SUPPLY CIRCUIT TO THE RH 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 PI11, pin 2 (UY)

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 K6

K6 : CHECK THE CONSTANT CIRCUIT OF THE RH CATALYST MONITOR SENSOR FOR OPEN CIRCUIT
1. Disconnect the RH catalyst monitor sensor electrical connector, PI11.
2. Disconnect the PCM electrical connector, PI01.
3. Measure the resistance between PI11, pin 3 (B) and PI01, pin 130 (BW)

Is the resistance less than 5 ohms?

Yes
Goto K7

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

K7 : CHECK THE CONSTANT CIRCUIT OF THE RH 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 K8

K8 : CHECK THE CONSTANT CIRCUIT OF THE RH 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 PI11, 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 K9

K9 : CHECK THE VARIABLE CIRCUIT OF THE RH CATALYST MONITOR SENSOR FOR OPEN CIRCUIT
1. Disconnect the RH catalyst monitor sensor electrical connector PI11.
2. Disconnect the PCM electrical connector, PI01.
3. Measure the resistance between PI01, pin 128 (N) and PI11, pin 4 (N)

Is the resistance less than 5 ohms?

Yes
Goto K10

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

K10 : CHECK THE VARIABLE CIRCUIT OF THE RH CATALYST MONITOR SENSOR FOR SHORT TO GROUND
1. Measure the resistance between PI11, 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 K11

K11 : CHECK THE VARIABLE CIRCUIT OF THE RH 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 PI11, pin 4 (N) and GROUND.

Is the voltage greater than 5 volts?

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

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