Rick's Free Auto Repair Advice

Jeep P0158

Diagnose and fix Jeep P0158

A Jeep P0158 trouble code relates to the downstream oxygen sensor on Bank 2. The full definition is: P0158 Heated Oxygen Sensor (Bank 2 Sensor 2) Voltage High. Do not just replace the oxygen sensor without doing at least some diagnostic work on the circuit. I’ve included the Jeep P0158 wiring diagram below.

Possible causes of Jeep P0158

B2S2 O2 sensor has failed due to contamination, silicone or water
The B2S2 O2 sensor circuit wiring is OPEN or Shorted to Voltage
The B2S2 O3 sensor connector is damaged or a pin has moved out of place
The B2S2 heater ground circuit is open.

How to test the O2 sensor when you have a Jeep P0158

Remove the electrical connector from the downstream O2 sensor on the Bank 2 side
Turn the key to the RUN position and check for battery voltage on pin 2. Then check for good ground on pin 1.

Jeep wiring diagram downstream oxygen sensor

Jeep P0158 troubleshooting

Reconnect the connector and start the engine. Backprobe pin 4 and read the downstream signal voltage. It should switch between 2.5-3.5 volts. If it doesn’t, swap it with the downstream sensor from Bank 1. If the Bank 1 sensor works, replace the sensor. If it doesn’t you’ve got a wiring harness or ground connection issue.

©, 2018 Rick Muscoplat

Posted on by Rick Muscoplat

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