DTC P0132 O2S Circuit High Voltage Sensor 1. Isuzu S/T Isuzu

For 1990-2009 cars only

Makes 🢒 Isuzu 🢒 2000 🢒 S/T Isuzu - 2WD 🢒 DTC 🢒 DTC P0132 O2S Circuit High Voltage Sensor 1

Circuit Description

The powertrain control module (PCM) supplies a voltage of about 0.45 volts to the oxygen sensor 1 (O2S 1). The O2S 1 varies the voltage between a range of about 1.0 volts if the exhaust is rich, down through about 0.10 volts if the exhaust is lean.

The O2S 1 is like an open circuit and produces no voltage when the O2S 1 temperature is below 315°C (600°F). An open O2S 1 circuit or cold sensor causes an Open Loop operation.

Conditions For Running The DTC

•	DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0169, P0171, P0172, P0178, P0179, P0201, P0202, P0203, P0204, P0300, P0336, P0440, P0446, P0452, P0453, P0506, P0507, P0601, P0602, or P1441 are not set.

•	The engine coolant temperature (ECT) is more than 70°C (158°F).

•	Engine run time more than 10 seconds.

•	The throttle position (TP) angle is between 8 percent and 50 percent.

•	Engine has met the above conditions for 3.8 seconds.

•	Fuel level more than 10 percent.

•	System is in Closed Loop.

•	System voltage more than 11.7 volts.

•	Fuel ethanol composition less than 88 percent.

Conditions For Setting The DTC

O2S 1 voltage is more than 946 mV for 50 seconds.

O2S 1 voltage is more than 1042 mV for 2.5 seconds while in DFCO.

Action Taken When the DTC Sets

•	The malfunction indicator lamp (MIL) will illuminate after 2 consecutive ignition cycles in which the diagnostic runs with the malfunction active.

•	The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.

•	A history DTC stores.

Conditions for Clearing the MIL/DTC

•	The MIL will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault.

•	A history DTC will clear after 40 consecutive warm up cycles without a fault.

•	A scan tool can clear the DTCs.

Diagnostic Aids

The DTC P0132 or the rich exhaust is most likely caused by one of the following conditions:

•	The fuel pressure--The system will go rich if the fuel pressure is too high. The PCM can compensate for some increase. However, if the fuel pressure gets too high, a DTC P0132 will set. Refer to Fuel System Diagnosis .

•	A leaking injector --A leaking or faulty fuel injector can cause the system to go rich causing a DTC P0132. Refer to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F) .

•

The electronic ignition (EI) shielding--An open ground circuit may result in EMI or induced electrical noise. The PCM looks at this noise as crankshaft position (CKP) sensor pulses. The additional pulses result in a higher than actual engine speed signal. The PCM then delivers too much fuel causing the system to go rich. The engine tachometer will also show higher than actual engine speed which can help in diagnosing this problem.

•

The MAP sensor --An output that causes the PCM to sense a higher than normal manifold pressure or low vacuum, can cause the system to go rich. Disconnecting the MAP sensor will allow the PCM to set a fixed value for the MAP sensor. Substitute a different MAP sensor if the rich condition is gone while the sensor is disconnected.

•	The TP sensor-- An intermittent TP sensor output will cause the system to go rich due to a false indication of the engine accelerating.

•

An O2S 1 contamination --Inspect the O2S 1 for silicone contamination from fuel or use of improper RTV sealant. The O2S 1 may have a white powdery coating and result in a high but false voltage signal (rich exhaust indication). The PCM will then reduce the amount of fuel delivered to the engine causing a severe surge or driveability problem.

•

Whenever the oxygen sensor pigtail wiring, the connector or the terminal are damaged, replace the entire oxygen sensor assembly. Do not attempt to repair the wiring, the connectors or the terminals. In order for the sensor to function properly, the O2S 1 must have a clean air reference. The oxygen sensor wires obtains this clean air reference. Any attempt to repair the wires, the connectors or the terminals could result in the obstruction of the clean air reference. Any attempt to repair the wires, the connectors or the terminals could degrade the oxygen sensors performance.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data captured when the malfunction occurred. The scan tool stores this data for later reference.

This step determines if DTC P0132 is the result of a hard malfunction or an intermittent condition. It may be necessary to operate the vehicle within the Freeze Frame conditions and Conditions for Setting the DTC in order to duplicate the malfunction detected by the PCM.

This step tests the circuit for a short to voltage. A shorted circuit will show voltage above 500 mV. The maximum O2S 1 reading the scan tool will show is just above 1000 mV even if the actual short is a much higher voltage. The normal bias voltage is approximately 456 mV when the sensor is disconnected as read by the scan tool.

Program the replacement PCM and perform the Crankshaft Position System Variation Procedure. Refer to the latest Techline™ information for PCM programming.

Step

Action

Values

Yes

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Run the engine until the normal operating temperature is reached.
Use a scan tool in order to monitor the O2S 1 voltage for the sensor that applies to this DTC.

Is the O2S 1 voltage fixed more than the value specified?

946 mV

Go to Step 4

Go to Step 3

This DTC is intermittent.

Are any additional DTCs stored?

Go to applicable table

Go to Diagnostic Aids

Turn OFF the ignition.
Disconnect the O2S 1 connector.
Turn ON the ignition, with the engine OFF.
Use the scan tool in order monitor the O2S 1 voltage.

Is the O2S 1 voltage above the specified value?

500 mV

Go to Step 6

Go to Step 5

The O2S 1 is detecting a rich exhaust condition or may be contaminated. Check for one of the following conditions:

•	O2S 1 connector water intrusion

•	Silicon contaminated O2S 1

•	Fuel contaminated engine oil

•	EVAP canister purge condition. Refer to Evaporative Emission Control System Diagnosis .

•	Incorrect fuel pressure. Refer to Fuel System Diagnosis .

•	Rich fuel injectors. Refer to Fuel Injector Balance Test .

Repair any of the above or similar engine conditions as necessary.

Did you find a condition?

Go to Step 9

Go to Step 7

Repair the short to voltage in the O2S 1 signal circuit.
Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

Go to Step 9

Go to Step 8

Important: Before replacing a contaminated O2S 1 determine and repair the cause of the contamination.

Replace the O2S 1. Refer to Oxygen Sensor Replacement .

Is the action complete?

Go to Step 9

Important:: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

Go to Step 9

Use the scan tool in order to clear the DTCs.
Start the engine.
Allow the engine to idle until the engine reaches the normal operating temperature.
Select DTC and the Specific DTC function.
Enter the DTC number which was set.
Operate the vehicle within the Conditions for Setting this DTC, until the scan tool indicates the diagnostic Ran.

Does the scan tool indicate the diagnostic Passed?

Go to Step 10

Go to Step 2

Does the scan tool display any additional undiagnosed DTCs?

Go to applicable DTC table

System OK