DTC P0132 Front Heated Oxygen Sensor (HO2S1) High Voltage

Diagnostic Trouble Code (DTC) P0132

Front Heated Oxygen Sensor (HO2S1) High Voltage



Circuit Know-how


  • Terminals M12 and M29 receive a voltage of about 0.45 volts which the ECM brings (in case it is measured with a 10 megaohm digital voltmeter then this voltage may read as low as 0.32 volts).
  • In case of a rich exhaust the Front Heated Oxygen sensor 1 (HO2S1) varies the voltage within a range of about 1 volt and down through about 0.10 volts for the reverse condition.
  • The sensor which acts similar to an open circuit does not generate any voltage when it is < 315°C(600°F).
  • An Open Loop operation is boosted by an open sensor circuit or cold sensor.
  • The full HO2S1 assembly needs to be changed on condition that the HO2S1 pigtail wiring, connector, or terminal is damaged.
  • You must not try to change the wiring, connector, or terminals because this might result in the blockade of the air reference and affect the HO2S1 performance.
  • So that the sensor functions properly, it must be supplied a clean air reference attached to it.
  • The clean air reference mentioned above is received from the HO2S1 wire(s).
  • Consult "Front Heated Oxygen Sensor" in this section.



When will DTC set?

Task boosted after DTC sets

When will DTC clear?

DTC sets when

1) HO2S1 voltage > 0.952 volts.

1) The Malfunction Indicator Lamp (MIL) will be seen to glow.

1) The MIL will go off after four consecutive ignition cycles where the diagnostic is found running faultlessly.


2) Closed loop stoichiometry condition prevails.

2) The ECM will begin to record operating conditions when the diagnostic fails.

2) A history DTC will automatically clear after 40 consecutive warm-up cycles faultlessly.

3) Engine Coolant Temperature (ECT) > 60°C (140°F).


3) This information will be stored in the Freeze Frame and Failure Records will be boosted.

3) The Scan Tool can be used to unset all DTCs.

4)  System voltage > 10 volts.


4) A history DTC is stored.

4) If the ECM battery feed is dissociated for more than 10 seconds.

5) 3 second delay conditions are met.

5)  The vehicle will operate in Open Loop.


6)  DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0336, P0337, P0351, P0352, P0402, P0404, P0405, P0406, P0506, P0507, P1404, and P0443 are not set.






Diagnostic Assistance


The DTC P0132 or rich exhaust is will be set when one of these criteria prevails:

·   Fuel pressure - The system will be found to be rich if the fuel pressure is found to be excessively high. The ECM can buffer for some such increase, but if it continues to high, a DTC P0132 will be set.

·   Leaking injector - A leaking/malfunctioning injector may turn the system rich boosting a DTC P0132.

·   Manifold Absolute Pressure (MAP) sensor - An output enabling the ECM to sense a manifold pressure (low vacuum) which is more than the usual can turn the system rich. In such a situation if you dissociate the MAP sensor then it will enable the ECM to replace a fixed value for the MAP sensor. When the rich condition is eliminated then changing the MAP sensor while the sensor is disconnected may help.

·   Pressure regulator – Probe for the existence of a leaking fuel pressure regulator diaphragm by checking if there is any liquid fuel in the vacuum line to the regulator.

·   TP sensor - An intermittent TP sensor output will make the system rich due to a false indication of the accelerating engine.

·   HO2S1 contamination - Probe the HO2S1 for the existence of silicone contamination from fuel or the use of improper Room Temperature Vulcanizing sealant. You may see that the sensor having a white powdery coating which may set up a high but false voltage signal (rich exhaust indication). In such a situation the task of the ECM will be to reduce the amount of fuel supplied to the engine, resulting in a massive surge or driveability problem.

Purpose of the test

Number(s) below refer to the step number(s) on the Diagnostic Table.

1.The On-Board Diagnostic (EOBD) System Check prepares the technician to undertake some routine checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. This data is then stored on the scan tool for future use.

2.This step is to see whether DTC P0132 results due to a hard failure or an intermittent condition. It may necessitate to  control the vehicle within the Freeze Frame conditions and Conditions for Setting the DTC in order to duplicate the malfunction detected by the ECM.

4.This step simulates a DTC P0131. If the ECM successfully detects the variation then it is deemed that the ECM and the wiring are OK.

6.The substitution of the ECM must be reprogrammed. You need to consult  the latest Techline procedure for ECM reprogramming.

8.If  you fail to find any malfunctions at this point and no additional DTCs were set, consult "Diagnostic Aids" in this section for additional checks and information.





DTC P0132 - Front Heated Oxygen Sensor (HO2S1) High Voltage








Execute an EOBD System Check.


Job carried out?


Follow Step 2


"On-Board Diagnostic System Check"


  1. Link up a scan tool to the Data Link Connector (DLC).
  2. Switch the ignition ON.

Do you see that the Front Heated Oxygen Sensor (HO2S1) voltage < the value specified?



Follow Step 4

Follow Step 3


  1. Read the Freeze Frame data and observe the parameters.
  2. Control the vehicle within the Freeze frame conditions and Conditions For Setting the DTC as noted.

Do you see that the HO2S1 voltage remaining below the specified value?


Follow Step 4

Follow Step 7


  1. Switch OFF the ignition.
  2. De-link HO2S1 connector.
  3. Turn ON the ignition.
  4. Jumper the Engine Control Module (ECM) side HO2S1 signal circuit to ground

Do you see the scan tool displaying the HO2S1 voltage < the value stated?


500 mV


"Diagnostic Aids"

Follow Step 5


Inspect the HO2S1 signal circuit, terminal 4 to see if there exists a short to ground and repair as needed.


Do you contemplate an urgent repair?


Follow Step 7

Follow Step 6


1)       Switch OFF the ignition.

2)       Change ECM.

Job Over?


Follow Step 7



  1. Re-link the HO2S1 connector if it was kept dissociated.
  2. Clear all DTCs taking a Scan Tool.
  3. Start the engine and let it idle at normal operating temperature.
  4. Regulate the vehicle within the Conditions for setting this DTC as specified in the supporting text.

Do you see that the scan tool is displaying that this diagnostic was run and passed?


Follow Step 8

Follow Step 2


Probe if any additional DTCs are still set.


Do you see any DTCs displayed that have not been diagnosed?


Follow applicable DTC table

The System of the vehicle is fine