picked up my car last night after a bunch of new mods were installed (supercharger upgrades, exhaust, etc), and threw a code last night, and again this morning while on the way to work.

P0134 Heated Oxygen Sensor (HO25) Circuit Insufficient Activity Bank 1 Sensor 1-A

i'm at work now, without my service manuals, and have never seen this code before.

what causes it, how do i fix it, and how much are the parts? any danger in driving the car hard until it is fixed?

(i'm guessing it is a bad front oxygen sensor)

thanks,
kw

 

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 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 and detects if the voltage goes out of the bias range. If the PCM does not detect the voltage went out of the bias range, 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 AIR and the Catalyst diagnostics are not active.
The fuel system is operating in Closed Loop.
The engine run time is greater than 70 seconds .
CONDITIONS FOR SETTING THE DTC


The HO2S signal voltage remains between 350 mV and 550 mV .
The conditions present for 60 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 the malfunction indicator lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and Des not fail.
A last test failed (current DTC) clears when the diagnostic runs and does not fail.
A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
Use a scan tool in order to clear the MIL/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 Diagrams.
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 Testing for Intermittent and Poor Connections in Diagrams.
For an intermittent condition, refer to Symptoms. See: Diagnostic Information and Procedures\Symptoms
TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.


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.
If the scan tool indicates the HO2S voltage goes below 200 mV , this indicates the HO2S circuits and PCM are OK.
This step verifies whether the tow signal circuit from the PCM is OK. A voltage indicates the PCM and wiring are OK.
This step verifies whether the signal circuit from the PCM is OK.
Disconnecting the PCM allows using a DMM in order to test continuity of the circuits. This aids in locating an open or shorted circuit.

 

thanks man! :) :cheers:

 

fyi, (for anybody else who searches for this thread) since i don't have a techII, i am going to check the following:

1. unplugged left front o2 sensor (the error code is persistent and Current)
2. front sensor plugged into rear sensor connector
3. bad o2 sensor

how this does it. i'll post a follow up after my lunch break [read: after i drive down to MCR ... heheh]

 

final follow up - got the c5 up on a lift and found that the left front oxygen sensor had not been reconnected when the headers were reinstalled last week.

so, a disconnected front oxygen sensor is one problem that will cause the P0134 code to be thrown.

my c5 is finally fixed and back on the road now. it sure as hell loves this 18 degree weather too. getting 4-6" of snow tonight/tomorrow though, so its going into hibernation for a while. :(

 

Glad that is all it was and that you could fix it! Best wishes for the holiday. :yesnod: :)