How To Diagnose Trouble Code P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
Troubleshooting a P0132 involves 2 basic things. First, you need to check that the upstream O2 sensor's wiring is not shorted to the exhaust pipe. This means checking that the oxygen sensor's wiring is not melted and stuck to the exhaust pipe.
NOTE: Check the oxygen sensor's wiring for shorts with the engine completely cold! The exhaust pipe, and especially the catalytic converter, stay very hot even after the engine has been shut down. Be careful and use common sense to avoid severe burns on your hands and/or arms while inspecting the upstream oxygen sensor's wiring!
Second, you need to confirm that the front (upstream) O2 sensor voltage is really producing an excessive high voltage with a scan tool. This scan tool has to have Live Data capability so you can see the actual voltage the oxygen sensor is producing/reporting (Don't have a scan tool? Need a scan tool? check out my recommendation: Actron CP9580 Scan Tool Review).
Don't worry, in the test steps below, I'll show you how to test the upstream oxygen sensor with a scan tool.
This is what you'll need to do:
Connect your scan tool to your car or mini-van and start the engine (Don't have a scan tool? Need a scan tool? check out my recommendation: Actron CP9580 Scan Tool Review).
Let the engine idle for at least 15 minutes before you start the test, to get the O2 sensor to activate.
Now, on your scan tool (and once you're in Live Data mode), scroll down to the PID that's labeled O2S11. This PID is the one that will show you what the oxygen sensor is reporting in Volts DC.
Now, take a look at the voltage readings for O2S11.
These should be constantly moving between any number between 0.100 Volts and 0.900 Volts.
If the voltages are not moving between 0.100 and 0.900 Volts, don't worry about it just yet. Go on to the next step.
With the engine running, start to disconnect a big vacuum hose while you observe your scan tool's display screen to get the air/fuel mixture to Lean out.
Note: I suggest removing the positive crankcase ventilation (PCV) hose to get the air/fuel mixture to lean out. See photo 2 of 2 in the image viewer.
What you're trying to accomplish, by unseating the PCV valve, is to produce a lean condition. By manually forcing a Lean condition, you and I can see if the upstream oxygen sensor will ‘see’ and report it to the PCM (which we'll be able to see on our scan tool, in Live Data mode of course).
As ambient air starts to get sucked into the vacuum hose's port, you should see the voltage numbers of O2S11 immediately go down to about 0.100 Volts.
Reconnecting the vacuum hose and see if the O2 sensor's reading goes back to its previous activity.
Let's take a look at what your test results mean:
CASE 1: The upstream O2 sensor's voltage decreased to 0.1 Volt This confirms that the upstream oxygen sensor is OK and responding to the changes in the air/fuel mixture.
This also means that the high voltage the upstream O2 sensor is reporting is being caused by a genuine Rich condition. Your next steps are to see why excessive fuel is being dumped into the cylinders (and thus causing a Rich condition). Here are some suggestions:
- Check fuel pressure, with a fuel pressure gauge, to see if it's too high.
- Check for leaking fuel injectors.
- EVAP canister vacuum hose leaking fuel into the intake manifold.
- A throttle position sensor (TPS) that is failing intermittently.
- Make sure all tune up parts (spark plugs, spark plug wires, distributor cap, etc.) don't have excessive wear and tear.
- Check for low engine compression.
CASE 2: The upstream O2 sensor's voltage DID NOT decrease to 0.1 Volts. This tells you that the upstream oxygen sensor is bad and needs to be replaced.
If the oxygen sensor was operating normally, it would have reacted to the removal of the PCV valve (from the valve cover) immediately by producing a voltage around 0.1 Volts (100 millivolts) since it did not, you can deduce correctly that it's fried and needs to be replaced.
CASE 3: The upstream O2 sensor's wiring is melted to the exhaust pipe. Replace the upstream oxygen sensor.