Running rough this morning... DIC Code: P0151
02-01-2008, 02:02 PM
#1
Racer
Thread Starter
Running rough this morning... DIC Code: P0151
Started to sputter this morning on my way into work. Never came close to stalling, but just had a very noticeable sputter at about ~2000rpm. I pulled over just to check and then the Check Engine light came on. Seemed to run okay after awhile.
I pulled the DIC and had the following in the H and C category:
P0151 - Heated Oxygen Sensor (HO2S) Circuit Low Voltage Bank 2 Sensor 1
There were others, but those were all in the H category. Does anyone know what could be causing the P0151 code? It obviously thinks there's an issue with the HO sensor, but (in layman's terms...) what is it, where is it located and which one is "Bank 2 Sensor 1"??? What would I check to troubleshoot or fix it?
I searched the forum for that code, but came up with very little results specific to that particular code. Anyway, I cleared the code and am going to see if it comes back on when I drove home. Maybe it's a false alarm, but what concerns me is the car was running rough when the light came.
Any info would be helpful and appreciated. Thanks!
EDIT:
=======================
BTW, some things I did last night prior to running the car this morning and getting the error:
1. Took off and re-installed the Fuel Rail Covers on both sides - Wanted to take some measurements. Could I have knocked something loose? Perhaps something feeding the HO Bank2 Sensor 1 or even the sensor itself???
2. Recharged my A/C freon - Have a leak so I've been recharging it until I can get it fixed. While recharging I had my engine cranked up to around 1800~2000RPM with full A/C blowing. Could that have damaged or impacted the HO Sensor?
I pulled the DIC and had the following in the H and C category:
P0151 - Heated Oxygen Sensor (HO2S) Circuit Low Voltage Bank 2 Sensor 1
There were others, but those were all in the H category. Does anyone know what could be causing the P0151 code? It obviously thinks there's an issue with the HO sensor, but (in layman's terms...) what is it, where is it located and which one is "Bank 2 Sensor 1"??? What would I check to troubleshoot or fix it?
I searched the forum for that code, but came up with very little results specific to that particular code. Anyway, I cleared the code and am going to see if it comes back on when I drove home. Maybe it's a false alarm, but what concerns me is the car was running rough when the light came.
Any info would be helpful and appreciated. Thanks!
EDIT:
=======================
BTW, some things I did last night prior to running the car this morning and getting the error:
1. Took off and re-installed the Fuel Rail Covers on both sides - Wanted to take some measurements. Could I have knocked something loose? Perhaps something feeding the HO Bank2 Sensor 1 or even the sensor itself???
2. Recharged my A/C freon - Have a leak so I've been recharging it until I can get it fixed. While recharging I had my engine cranked up to around 1800~2000RPM with full A/C blowing. Could that have damaged or impacted the HO Sensor?
Last edited by egypt123; 02-01-2008 at 02:11 PM. Reason: Added info for clarity
02-01-2008, 02:46 PM
#2
Safety Car
Well for whatever reason your oxygen sensor is not happy. Bank 2 Sensor 1 would be the O2 sensor located on the passenger side exhaust just before the catalytic converter.
02-01-2008, 03:01 PM
#3
Le Mans Master
Here you go, Good Luck !
Document ID# 316692
1999 Chevrolet/Geo Corvette
--------------------------------------------------------------------------------
DTC P0151 HO2S Circuit Low Voltage Bank 2 Sensor 1
Circuit Description
The PCM supplies a voltage of about 450 mV between the HO2S high and low signal circuits. The oxygen sensor varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean.
The PCM monitors and stores the heated oxygen sensor (HO2S) voltage information. The PCM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. The PCM compares the stored HO2S voltage samples taken within each sample period and determines if majority of the samples are out of the operating range.
The PCM monitors the HO2S voltage for being fixed below a predetermined voltage. If the PCM detects the voltage is below a predetermined voltage, a DTC sets.
Conditions for Running the DTC
DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0125, P0200, P0335, P0336, P0351-P0358, P1120, P1220, P1221, P1258 are not set.
The ignition voltage is greater than 9.0 volts.
The fuel system is operating in Closed Loop.
The AIR and the Catalyst diagnostics are not active.
The TP angle is between 2% and 70%.
Conditions for Setting the DTC
The HO2S signal voltage remains below 200 mV.
The conditions are present for 31 seconds.
Action Taken When the DTC Sets
The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Use a scan tool in order to clear the MIL and the DTC.
Diagnostic Aids
Important
Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.
For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A . Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Wiring Systems.
The PCM sets this DTC when the vehicle runs out of fuel.
Heated Oxygen Sensor (HO2S) wire: Sensor pigtail may be in contact with the exhaust manifold or the exhaust system.
An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provides the supply of oxygen. Inspect the HO2S wires and connections for breaks or contamination. Refer to Wiring Repairs in Wiring Systems.
Inspect for an intermittent ground in the signal wire between the connector and the sensor.
Lean injector(s): Perform the Injector Balance Test. Refer to Fuel Injector Balance Test with Tech 2 or Fuel Injector Balance Test with Special Tool .
Fuel contamination: Water near the in-tank fuel pump inlet can be delivered to the injectors. The water causes a lean exhaust and can set a DTC. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
Fuel pressure: System will be lean if fuel pressure is low. Refer to Fuel System Diagnosis .
Exhaust leaks: An exhaust leak near the HO2S can cause a lean condition. Refer to Inspection Procedure in Engine Exhaust.
Vacuum or crankcase leaks can cause a lean condition.
If the above are OK, the HO2S may be at fault.
For an intermittent condition, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
If the HO2S voltage is fixed well below 200 mV, this indicates a short to battery ground or chassis ground. If the voltage is fixed near or above 200 mV, this indicates a short to a PCM ground.
The engine must be at the normal operating temperature before performing this test.
Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you can not duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that the PCM recorded. This isolates when the DTC failed.
A sensor that is disconnected should indicate a bias voltage. If the voltage is low inspect the signal circuit for a short to ground in Wiring Systems.
Disconnecting the PCM allows using a DMM in order to test continuity of the circuits. This aids in locating an open or shorted circuit.
Step
Action
Value(s)
Yes
No
1
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check
2
Important
Inspect the HO2S for being secure before proceeding with this DTC. A sensor that is loose could cause this DTC to set.
Install a scan tool.
Idle the engine at the normal operating temperature.
Operate the vehicle within the parameters specified under Conditions for Running the DTC in the supporting text.
Monitor the HO2S voltage display on the Engine 1 Data List using the scan tool.
Is the HO2S voltage less than the specified value?
200 mV
Go to Step 4
Go to Step 3
3
Turn ON the ignition leaving the engine OFF.
Review the Freeze Frame and/or Failure Records data for this DTC and observe the parameters.
Turn OFF the ignition for 15 seconds.
Idle the engine.
Operate the vehicle within the conditions required for this diagnostic to run, and as close to the conditions recorded in Freeze Frame/Failure Records as possible. Special operating conditions that need to be met before the PCM will run this diagnostic, where applicable, are listed in Conditions for Running the DTC.
Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
Does the scan tool indicate that this diagnostic failed this ignition?
--
Go to Step 4
Go to Diagnostic Aids
4
Disconnect the HO2S.
Jumper the HO2S low circuit (PCM side) to a known good ground.
Monitor the HO2S voltage using the scan tool.
Does the scan tool indicate the HO2S voltage within the specified range?
350-550 mV
Go to Diagnostic Aids
Go to Step 5
5
Turn OFF the ignition.
Disconnect the PCM connector C1 located on the same side as the manufacturer's logo. Refer to PCM/TAC Module Replacement .
Test the HO2S signal circuit for a short to ground or a short to the sensor ground circuit. Refer to Testing for Short to Ground in Wiring Systems.
Is the HO2S signal circuit shorted?
--
Go to Step 6
Go to Step 7
6
Repair the HO2S signal circuit. Refer to Wiring Repairs in Wiring Systems.
Is the action complete?
--
Go to Step 10
--
7
Important
Program the replacement PCM. Refer to PCM/TAC Module Replacement .
Replace the PCM.
Is the action complete?
--
Go to Step 10
--
8
Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option using the scan tool.
Idle the engine at the normal operating temperature.
Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.
Does the scan tool indicate that this test ran and passed?
--
Go to Step 9
Go to Step 2
9
Select the Capture Info option and the Review Info option using the scan tool.
Does the scan tool display any DTCs that you have not diagnosed?
--
Go to the applicable DTC table
System OK
--------------------------------------------------------------------------------
Document ID# 316692
1999 Chevrolet/Geo Corvette
Document ID# 316692
1999 Chevrolet/Geo Corvette
--------------------------------------------------------------------------------
DTC P0151 HO2S Circuit Low Voltage Bank 2 Sensor 1
Circuit Description
The PCM supplies a voltage of about 450 mV between the HO2S high and low signal circuits. The oxygen sensor varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean.
The PCM monitors and stores the heated oxygen sensor (HO2S) voltage information. The PCM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. The PCM compares the stored HO2S voltage samples taken within each sample period and determines if majority of the samples are out of the operating range.
The PCM monitors the HO2S voltage for being fixed below a predetermined voltage. If the PCM detects the voltage is below a predetermined voltage, a DTC sets.
Conditions for Running the DTC
DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0125, P0200, P0335, P0336, P0351-P0358, P1120, P1220, P1221, P1258 are not set.
The ignition voltage is greater than 9.0 volts.
The fuel system is operating in Closed Loop.
The AIR and the Catalyst diagnostics are not active.
The TP angle is between 2% and 70%.
Conditions for Setting the DTC
The HO2S signal voltage remains below 200 mV.
The conditions are present for 31 seconds.
Action Taken When the DTC Sets
The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Use a scan tool in order to clear the MIL and the DTC.
Diagnostic Aids
Important
Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.
For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A . Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Wiring Systems.
The PCM sets this DTC when the vehicle runs out of fuel.
Heated Oxygen Sensor (HO2S) wire: Sensor pigtail may be in contact with the exhaust manifold or the exhaust system.
An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provides the supply of oxygen. Inspect the HO2S wires and connections for breaks or contamination. Refer to Wiring Repairs in Wiring Systems.
Inspect for an intermittent ground in the signal wire between the connector and the sensor.
Lean injector(s): Perform the Injector Balance Test. Refer to Fuel Injector Balance Test with Tech 2 or Fuel Injector Balance Test with Special Tool .
Fuel contamination: Water near the in-tank fuel pump inlet can be delivered to the injectors. The water causes a lean exhaust and can set a DTC. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
Fuel pressure: System will be lean if fuel pressure is low. Refer to Fuel System Diagnosis .
Exhaust leaks: An exhaust leak near the HO2S can cause a lean condition. Refer to Inspection Procedure in Engine Exhaust.
Vacuum or crankcase leaks can cause a lean condition.
If the above are OK, the HO2S may be at fault.
For an intermittent condition, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
If the HO2S voltage is fixed well below 200 mV, this indicates a short to battery ground or chassis ground. If the voltage is fixed near or above 200 mV, this indicates a short to a PCM ground.
The engine must be at the normal operating temperature before performing this test.
Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you can not duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that the PCM recorded. This isolates when the DTC failed.
A sensor that is disconnected should indicate a bias voltage. If the voltage is low inspect the signal circuit for a short to ground in Wiring Systems.
Disconnecting the PCM allows using a DMM in order to test continuity of the circuits. This aids in locating an open or shorted circuit.
Step
Action
Value(s)
Yes
No
1
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check
2
Important
Inspect the HO2S for being secure before proceeding with this DTC. A sensor that is loose could cause this DTC to set.
Install a scan tool.
Idle the engine at the normal operating temperature.
Operate the vehicle within the parameters specified under Conditions for Running the DTC in the supporting text.
Monitor the HO2S voltage display on the Engine 1 Data List using the scan tool.
Is the HO2S voltage less than the specified value?
200 mV
Go to Step 4
Go to Step 3
3
Turn ON the ignition leaving the engine OFF.
Review the Freeze Frame and/or Failure Records data for this DTC and observe the parameters.
Turn OFF the ignition for 15 seconds.
Idle the engine.
Operate the vehicle within the conditions required for this diagnostic to run, and as close to the conditions recorded in Freeze Frame/Failure Records as possible. Special operating conditions that need to be met before the PCM will run this diagnostic, where applicable, are listed in Conditions for Running the DTC.
Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
Does the scan tool indicate that this diagnostic failed this ignition?
--
Go to Step 4
Go to Diagnostic Aids
4
Disconnect the HO2S.
Jumper the HO2S low circuit (PCM side) to a known good ground.
Monitor the HO2S voltage using the scan tool.
Does the scan tool indicate the HO2S voltage within the specified range?
350-550 mV
Go to Diagnostic Aids
Go to Step 5
5
Turn OFF the ignition.
Disconnect the PCM connector C1 located on the same side as the manufacturer's logo. Refer to PCM/TAC Module Replacement .
Test the HO2S signal circuit for a short to ground or a short to the sensor ground circuit. Refer to Testing for Short to Ground in Wiring Systems.
Is the HO2S signal circuit shorted?
--
Go to Step 6
Go to Step 7
6
Repair the HO2S signal circuit. Refer to Wiring Repairs in Wiring Systems.
Is the action complete?
--
Go to Step 10
--
7
Important
Program the replacement PCM. Refer to PCM/TAC Module Replacement .
Replace the PCM.
Is the action complete?
--
Go to Step 10
--
8
Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option using the scan tool.
Idle the engine at the normal operating temperature.
Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.
Does the scan tool indicate that this test ran and passed?
--
Go to Step 9
Go to Step 2
9
Select the Capture Info option and the Review Info option using the scan tool.
Does the scan tool display any DTCs that you have not diagnosed?
--
Go to the applicable DTC table
System OK
--------------------------------------------------------------------------------
Document ID# 316692
1999 Chevrolet/Geo Corvette
