Powertrain Codes

P0142

Technical Definition:

O2 Circuit (Bank 1, Sensor 3)

Trouble Code: P0142
Address: 0x0142
System: Powertrain
Subsystem:
Technical Description:

The oxygen sensors are critical to the engine running properly. It basically informs the PCM (Powertrain Control Module) of oxygen content of the exhaust. The PCM then uses this information to regulate fuel injector pulse. Inaccurate or faulty O2 sensors can cause the PCM to add or take away fuel based on the faulty O2 sensor voltage which can cause a host of problems.

Possible Causes:
  • Bad O2 sensor
  • Signal shorted to voltage
  • Wiring problems due to contact with exhaust components
  • Holes in exhaust near O2 sensor

Possible Symptoms:
  • MIL (Malfunction Indicator Lamp) illumination
  • Decrease in MPG
  • Increase in tailpipe emissions

O2 Sensor Circuit Malfunction Bank 1 Sensor 3

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Heated Oxygen Sensor Bank 1 Sensor 3
– Heated Oxygen Sensor Bank 1 Sensor 3 harness is open or shorted
– Heated Oxygen Sensor Bank 1 Sensor 3 circuit poor electrical connection

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust

P0143

Technical Definition:

O2 Circuit Low Voltage (Bank 1, Sensor 3)

Trouble Code: P0143
Address: 0x0143
System: Powertrain
Subsystem:
Technical Description:

The Catalytic Converter is used to help control emissions. The PCM (Powertrain Control Module) uses the signal from the oxygen sensor to the rear of the catalyst to monitor the catalyst’s efficiency.

Possible Causes:
  • Air leaks in exhaust in front of o2 sensor giving false reading
  • O2 sensor connector damaged
  • O2 sensor signal circuit is shorted to ground
  • O2 sensor ground circuit is open
  • O2 sensor has failed (it may be contaminated with fuel or coolant)
  • PCM has failed

Possible Symptoms:
  • MIL (Malfunction Indicator Lamp) illumination
  • Engine performance issues
  • Engine running rough
  • Engine running rich
  • Poor idle

O2 Sensor Circuit Low Voltage Bank 1 Sensor 3

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Heated Oxygen Sensor Bank 1 Sensor 3
– Heated Oxygen Sensor Bank 1 Sensor 3 harness is open or shorted
– Heated Oxygen Sensor Bank 1 Sensor 3 circuit poor electrical connection

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust

P0144

Technical Definition:

O2 Circuit High Voltage (Bank 1, Sensor 3)

Trouble Code: P0144
Address: 0x0144
System: Powertrain
Subsystem:
Technical Description:

The catalytic converter is used to lower harmful emissions. To ensure proper operation, there is an O2 sensor located behind the catalyst that monitors the oxygen content of the exhaust after the cat. The PCM (Powertrain Control Module) then compares the post-cat reading to the pre-cat readings to determine if the catalyst is working properly.

Possible Causes:
  • ad o2 sensor (Bank 1 Sensor 3)
  • Wiring in contact with exhaust components
  • Engine running rich (If other codes are present)
  • Holes in exhaust near Bank 1 Sensor 3
  • Short to voltage on signal circuit
  • Bad PCM

Possible Symptoms:
  • MIL (Malfunction Indicator Lamp) on
  • Engine loses power and misses intermittently
  • May exhibit loss of fuel efficiency

O2 Sensor Circuit High Voltage Bank 1 Sensor 3

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Heated Oxygen Sensor Bank 1 Sensor 3
– Heated Oxygen Sensor Bank 1 Sensor 3 harness is open or shorted
– Heated Oxygen Sensor Bank 1 Sensor 3 circuit poor electrical connection

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust

P0145

Technical Definition:

O2 Circuit Slow Response (Bank 1, Sensor 3)

Trouble Code: P0145
Address: 0x0145
System: Powertrain
Subsystem:
Technical Description:

Possible Causes:

Possible Symptoms:

O2 Sensor Circuit Slow Response Bank 1 Sensor 3

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Heated Oxygen Sensor Bank 1 Sensor 3
– Heated Oxygen Sensor Bank 1 Sensor 3 harness is open or shorted
– Heated Oxygen Sensor Bank 1 Sensor 3 circuit poor electrical connection

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust

P0146

Technical Definition:

O2 Circuit No Activity Detected (Bank 1, Sensor 3)

Trouble Code: P0146
Address: 0x0146
System: Powertrain
Subsystem:
Technical Description:

The catalytic converter is used to control emissions. The o2 sensor on Bank 1, position 3 is aft of the converter and monitors the catalyst efficiency. The PCM (Powertrain Control Module) does this by comparing the post-cat o2 sensor to the pre-cat o2 sensors.

Possible Causes:
  • Bad Bank 1, position 3, o2 sensor
  • Wiring problem, melted harness, broken connectors, etc.
  • Bad PCM

Possible Symptoms:
  • MIL (Malfunction Indicator Lamp) on
  • May idle or drive poorly
  • Fuel economy may decrease

O2 Sensor Circuit No Activity Detected Bank 1 Sensor 3

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Heated Oxygen Sensor Bank 1 Sensor 3
– Heated Oxygen Sensor Bank 1 Sensor 3 harness is open or shorted
– Heated Oxygen Sensor Bank 1 Sensor 3 circuit poor electrical connection

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust

P0140

Technical Definition:

O2 Circuit No Activity Detected (Bank 1, Sensor 2)

Trouble Code: P0140
Address: 0x0140
System: Powertrain
Subsystem:
Technical Description:

Possible Causes:

Possible Symptoms:

O2 Sensor Circuit No Activity Detected Bank 1 Sensor 2

Possible Solutions:

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Rear Heated Oxygen Sensor Bank 1
– Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
– Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
– Inappropriate fuel pressure
– Faulty fuel injectors
– Intake air leaks may be faulty
– Exhaust gas leaks

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust

P0141

Technical Definition:

O2 Heater Circuit (Bank 1, Sensor 2)

Trouble Code: P0141
Address: 0x0141
System: Powertrain
Subsystem:
Technical Description:

The heated circuit in the oxygen sensor on bank 1 decreases time needed to enter closed loop.

Possible Causes:
  • open or short to ground in the wiring harness
  • O2 heater circuit wiring high resistance
  • O2 heater element resistance is high
  • Internal short or open in the heater element

Possible Symptoms:

O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 2

Possible Solutions:
  • Replace oxygen sensor (cannot repair open or short that occurs internally to sensor)
  • Repair short or open or high resistance in wiring harness or harness connectors

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2
– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit fuse
– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit open shorted to ground
– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit poor electrical connection
– Faulty Engine Control Module (ECM)

Specific Makes:

– Possible higher than usual fuel Consumption

P0139

Technical Definition:

O2 Circuit Slow Response (Bank 1, Sensor 2)

Trouble Code: P0139
Address: 0x0139
System: Powertrain
Subsystem:
Technical Description:

The involves the rear oxygen sensor on the driver’s side. This code indicates the engine air fuel ratio is not being adjusted by the oxygen sensor signal or the ECM as expected to do so, or not adjusted as often as expected to do so once the engine is warmed or under normal engine use.

Possible Causes:
  • The oxygen sensor is faulty
  • The wiring to the sensor is broken / frayed
  • There is an exhaust leak

Possible Symptoms:

O2 Sensor Circuit Slow Response Bank 1 Sensor 2

Possible Solutions:
  • Check and fix any exhaust leaks
  • Check for wiring problems (shorted, frayed wires)
  • Check the frequency and amplitude of the oxygen sensor (advanced)
  • Check for a deteriorating / contaminated oxygen sensor, replace if necessary
  • Check for inlet air leaks
  • Check the MAF sensor for proper operation

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Rear Heated Oxygen Sensor Bank 1
– Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
– Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
– Inappropriate fuel pressure
– Faulty fuel injectors
– Intake air leaks may be faulty
– Exhaust gas leaks

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust

P0135

Technical Definition:

O2 Heater Circuit (Bank 1, Sensor 1)

Trouble Code: P0135
Address: 0x0135
System: Powertrain
Subsystem:
Technical Description:

The heated circuit in the oxygen sensor decreases time needed to enter closed loop.

Possible Causes:
  • O2 Heater element resistance is high
  • Internal short or open in the heater element
  • O2 heater circuit wiring high resistance
  • open or short to ground in the wiring harness

Possible Symptoms:

O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1

Possible Solutions:
  • Repair short or open or high resistance in wiring harness or harness connectors
  • Replace oxygen sensor

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1
– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit fuse
– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit open shorted to ground
– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit poor electrical connection
– Faulty Engine Control Module (ECM)

Specific Makes:

– Possible higher than usual fuel Consumption

P0136

Technical Definition:

O2 Circuit (Bank 1, Sensor 2) (See P2270, P2271)

Trouble Code: P0136
Address: 0x0136
System: Powertrain
Subsystem:
Technical Description:

Possible Causes:
  • Faulty O2 sensor leak in exhaust close to O2 sensor
  • Short to voltage on O2 signal circuit
  • Open in circuit resistance caused by corrosion in connector

Possible Symptoms:

O2 Sensor Circuit Malfunction Bank 1 Sensor 2

Possible Solutions:
  • Replace the second oxygen sensor on bank 1
  • Repair open or short in signal circuit
  • Clean corrosion from connector

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Rear Heated Oxygen Sensor Bank 1
– Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
– Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
– Inappropriate fuel pressure
– Faulty fuel injectors
– Intake air leaks may be faulty
– Exhaust gas leaks

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust

P0137

Technical Definition:

O2 Circuit Low Voltage (Bank 1, Sensor 2)

Trouble Code: P0137
Address: 0x0137
System: Powertrain
Subsystem:
Technical Description:

Possible Causes:
  • Faulty o2 sensor Exhaust leak near the rear sensor
  • Plugged catalyst
  • Short to voltage on O2 signal circuit
  • High resistance or open on O2 signal circuit
  • Engine running very rich or lean
  • Engine misfire condition
  • Fuel pressure very high or low – fuel pump or pressure regulator

Possible Symptoms:

O2 Sensor Circuit Low Voltage Bank 1 Sensor 2

Possible Solutions:
  • Replace faulty sensor
  • Repair exhaust leak near the rear sensor
  • Check for restriction in catalyst and replace as necessary
  • Repair short, open, or high resistance on o2 signal circuit

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty Rear Heated Oxygen Sensor Bank 1
– Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
– Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
– Inappropriate fuel pressure
– Faulty fuel injectors
– Intake air leaks may be faulty
– Exhaust gas leaks

Specific Makes:

– High Fuel Consumption
– Excessive Smoke from Exhaust