P1134 Code 03 Chevy Venture

I have a 03 Chevy Venture. I keep getting a code P1134 that says "Mil on monitrs 2 inc catlyst evap 6 ready misfire fuel comp 02 sensr 02 htr egr" - that is what comes up on the scanner. I have no idea what this means and my husband is deployed. I already changed the 02 senser and the spark plugs. Any ideas?

which sensor did you change? the one before the cat (in the exhaust manifold directly behind the engine? Did you reset the codes? Dont know what you mean by "Mil on monitrs 2 inc catlyst evap 6 ready misfire fuel comp 02 sensr 02 htr egr"
Sounds like a conglomeration of things..... Might check the website for your scanner for the code, I show it as being a slow sensor (pre cat) bank 1 sensor 1.

P1134 - O2 sensor heater circuit intermittent (bank 1, sensor 2)
bank 1 = driver side exhaust
sensor 2 = down stream sensor, after the catalytic converter.

The Heated O2 sensor cold have a burt, or broken wire.

Before I changed the O2 sensor I got the code P0135 which is for the upstream sensor. I replaced it and reset the code. After driving for about 2 days (very little drive time) the next code came up (P1134) which according to the manual means "oxygen sensor transition time ratio (upstream sensor)". I was told to change the spark plugs - which needed to be done anyway - this cleared the code on it's own. But again I drove for about 10 miles and it came right back on - same code. I don't know if maybe I got a bad O2 sensor or what to do.

The upstream HO2 sensors are used for the Air/fuel mix, the down stream HO2 sensor tell the ECU if your cat's are good.

If your H02 sensor on bank 1 sensor 2 is bad, it won't hurt your car.

Did you put the H20 sensor on?
What size is your engine ?
Do you have two banks on this car?

Yes I put the o2 sensor on an I have a 3.4 lt V6. When you say banks you mean the front and rear bank where the spark plugs go? If so then yes I have two banks.

Standing in front of car with the hood up, look @

Right side (drivers side) = bank 1, cylinders 1-3.
Left side (passenger side) = bank 2 , cylinders 4-6.

The dual exhaust runs all the way down to the rear tail pipes, the ECU also see both banks.

You could actually swap, or roll the down stream H02 sensors from bank 1 to bank 2,
and clear code.

I have front wheel drive and I have to rotate my engine just to access the rear bank, but I do understand what you are saying.

I have no idea how to "roll the down stream H02 sensors from bank 1 to bank 2, and clear code." If I just replace the down stream sensor will that do the same thing?

LOL - How did you replace it the 1st time?

Yes - you could throw another part at it, but you need todo a visual inspection on your H02 sensor wire.

I think you need todo this project from under the car.

When I replaced the upsteam sensor all I had to do was get under the van disconnect the electrical connector from the sensor, unscrew the sensor from the exhaust manifoild and reverse the steps to put the new one on. Everything was done under the car.

I will get under the van tomorrow and take a look at the wires. Thanks for your help

Oh wait do you mean switch the down stream senser with the upstream senser?

Bingo ! The H2O sensor on the exhaust manifold is sensor 1 (up stream), the H2O sensor after the catalytic converter is sensor 2 (down stream) , see www.youtube.com/watch?v=QQ393gnvm-k (http://www.youtube.com/watch?v=QQ393gnvm-k)
focus on the one after the cat.

Roll BANK 1 down stream O2 sensor with BANK 2 down stream.

The upstream and downstream O2 sensors are different and they have different plugs on them.

Here is a portion of the circuit description and troubleshooting data:
CIRCUIT DESCRIPTION
The Heated Oxygen sensor (HO2S) is a sensor designed to create a voltage relative to the oxygen content in the engine exhaust stream. The control module supplies the HO2S with signal high and low circuits. Ignition voltage and ground are supplied to the HO2S heater by independent circuits. The oxygen content of the exhaust indicates when the engine is operating lean or rich. When the HO2S detects that the engine is operating rich, the signal voltage is high, and decreases the signal voltage as the engine runs leaner. This oscillation above and below the bias voltage, sometimes referred to as activity or switching, can be monitored with the HO2S signal voltage.

The HO2S contains a heater that is necessary in order to quickly warm the sensor to operating temperature. The heater also maintains the operating temperature during extended idle conditions. The HO2S needs to be at a high temperature in order to produce a voltage. When the HO2S reaches operating temperature, the control module monitors the HO2S bias, or reference, voltage. It also monitors the HO2S signal voltage for Closed Loop fuel control.

During normal Closed Loop fuel control operation, the control module will add fuel, or enrich the mixture, when the HO2S detects a lean exhaust content. The control module will subtract fuel, or "lean-out" the mixture, when the HO2S detects a rich exhaust condition.

Certain vehicle (http://www.automotiveforums.com/vbulletin/#) models utilize an oxygen sensor behind the catalytic converter in order to monitor catalyst efficiency.

This Diagnostic Trouble Code (DTC) determines if the HO2S is functioning properly. It checks for an adequate number of HO2S voltage transitions above and below the bias range of 300-600 mV . This DTC sets when the Vehicle Control Module (VCM) fails to detect a minimum number of voltage transitions above and below the bias range during the test period. Possible causes of this DTC are:

* An open or a short to voltage on either the HO2S signal or HO2S low circuits
* A malfunctioning HO2S
* A problem in the HO2S heater or its circuit
* A faulty HO2S ground

The next step, in my opinion, would be to get it on a scanner capable of showing you live data from the O2 sensor and see if it is switching lean to rich. You can also see if the heater is working by monitoring the O2 voltage without the vehicle running and before starting it. Is it possible a wire has gotten burnt?

Just replaced the downstream O2 sensor, cleared the code, drove about 10 miles and the darn light came back on. Same code as I was getting before P1134! Now I have replaced both my O2 sensors and all my spark plugs. I have no idea what to even try next!

Do you have ANY exhaust leaks?

P1134 - HO2S Transition Time Ratio Bank 1 Sensor 1

Schematic
http://i11.photobucket.com/albums/a187/swartlkk/2000%20Bravada/th_P1134_sch.gif (http://i11.photobucket.com/albums/a187/swartlkk/2000%20Bravada/P1134_sch.gif)

CIRCUIT DESCRIPTION
The Heated Oxygen sensor (HO2S) is a sensor designed to create a voltage relative to the oxygen content in the engine exhaust stream. The control module supplies the HO2S with signal high and low circuits. Ignition voltage and ground are supplied to the HO2S heater by independent circuits. The oxygen content of the exhaust indicates when the engine is operating lean or rich. When the HO2S detects that the engine is operating rich, the signal voltage is high, and decreases the signal voltage as the engine runs leaner. This oscillation above and below the bias voltage, sometimes referred to as activity or switching, can be monitored with the HO2S signal voltage.

The HO2S contains a heater that is necessary in order to quickly warm the sensor to operating temperature. The heater also maintains the operating temperature during extended idle conditions. The HO2S needs to be at a high temperature in order to produce a voltage. When the HO2S reaches operating temperature, the control module monitors the HO2S bias, or reference, voltage. It also monitors the HO2S signal voltage for Closed Loop fuel control.

During normal Closed Loop fuel control operation, the control module will add fuel, or enrich the mixture, when the HO2S detects a lean exhaust content. The control module will subtract fuel, or "lean-out" the mixture, when the HO2S detects a rich exhaust condition.

Certain vehicle models utilize an oxygen sensor behind the catalytic converter in order to monitor catalyst efficiency.

This Diagnostic Trouble Code (DTC) determines if the HO2S is functioning properly. It checks for an adequate number of HO2S voltage transitions above and below the bias range of 300-600 mV . This DTC sets when the Vehicle Control Module (VCM) fails to detect a minimum number of voltage transitions above and below the bias range during the test period. Possible causes of this DTC are:

* An open or a short to voltage on either the HO2S signal or HO2S low circuits
* A malfunctioning HO2S
* A problem in the HO2S heater or its circuit
* A faulty HO2S ground

CONDITIONS FOR RUNNING THE DTC

* No active TP sensor DTCs
* No active EVAP system DTCs
* No active EAT sensor DTCs
* No active MAP sensor DTCs
* No active ECT sensor DTCs
* No active MAF sensor DTCs
* No active misfire DTCs
* No intrusive tests in progress
* The system voltage is between 11.7-18 volts .

Response Test Enable:

* The system is in Closed Loop.
* DTCs P0131, P0132, P0134, and P0135 not active
* The ECT is more than 57°C (135°F) .
* The engine has been running for more than 75 seconds .
* The MAF is between 15-55 g/s .
* The engine speed is between 1100-3000 RPM .
* EVAP canister purge is active.
* The above conditions are present for more than 2 seconds .

CONDITIONS FOR SETTING THE DTC
The average transition time over a 100 second sample period is not within a specified range.

ACTION TAKEN WHEN THE DTC SETS
The VCM illuminates the Malfunction Indicator Lamp (MIL) after 2 consecutive test failures. The VCM records the operating conditions at the time the diagnostic fails. The Freeze Frame/Failure Records store this information.

CONDITIONS FOR CLEARING THE MIL OR DTC

* The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed.
* A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle.
* Use a scan tool in order to clear the DTCs.

DIAGNOSTIC AIDS
Check for the following conditions:

* An improperly installed air cleaner outlet duct
* The air cleaner outlet duct for collapsed ducting, restrictions, or a missing or plugged air filter
* The throttle body and intake manifold vacuum leaks
* A damaged or blocked throttle body inlet
* Exhaust system for corrosion, leaks, or loose or missing hardware.
* The HO2S is installed securely and the pigtail harness is not contacting the exhaust manifold or wires.
* HO2S contamination
* The vacuum hoses for splits, kinks, and proper connections
* Excessive water, alcohol, or other contaminants in the fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis. See: Component Tests and General Diagnostics\Alcohol/Contaminants-in-Fuel Diagnosis
* VCM sensor grounds that are clean, tight, and properly positioned

An intermittent may be caused by any of the following conditions:

* A poor connection
* Rubbed through wire insulation
* A broken wire inside the insulation Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent and Poor Connections in Diagrams.

If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Diagrams.

Diagnostic Chart (Part 1 Of 3)
http://i11.photobucket.com/albums/a187/swartlkk/2000%20Bravada/th_P1134_diag1of3.gif (http://i11.photobucket.com/albums/a187/swartlkk/2000%20Bravada/P1134_diag1of3.gif)
Diagnostic Chart (Part 2 Of 3)
http://i11.photobucket.com/albums/a187/swartlkk/2000%20Bravada/th_P1134_diag2of3.gif (http://i11.photobucket.com/albums/a187/swartlkk/2000%20Bravada/P1134_diag2of3.gif)
Diagnostic Chart (Part 3 Of 3)
http://i11.photobucket.com/albums/a187/swartlkk/2000%20Bravada/th_P1134_diag3of3.gif (http://i11.photobucket.com/albums/a187/swartlkk/2000%20Bravada/P1134_diag3of3.gif)

TEST DESCRIPTION
The numbers below refers to the step numbers on the diagnostic table.

2. HO2S contamination is indicated if multiple response, switching or time ratio HO2S DTCs are set.

4. The use of leaded fuel may be indicated by the removal or tampering of the fuel filler restrictor. An HO2S contaminated by silicon will have a white, powdery deposit on the portion of the HO2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of un-approved silicon RTV engine gasket material or the use of silicon based sprays or fluids within the engine. If the cause of this contamination is not corrected, the replacement HO2S will also get contaminated.

7. Even small exhaust leaks can cause slow response from the HO2S.

12. An HO2S contaminated by silicon will have a white, powdery deposit on the portion of the HO2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of un-approved silicon RTV engine gasket material or the use of the use of silicon based sprays or fluids within the engine. If the cause of this contamination is not corrected, the replacement HO2S will also get contaminated.
13. If the voltage observed in step 8 is less than the range specified a short between the HIGH and LOW circuits or a short between the HIGH circuit and ground is indicated. With the HO2S and the VCM disconnected the resistance between the HIGH and LOW circuits and the resistance between the HIGH circuit and ground should measure infinite. If the voltage observed in step 8 is more than the range specified a short between the HIGH circuit and an ignition voltage source is indicated.
14. If the voltage observed in step 9 is not below the voltage specified a high resistance (open) HIGH or LOW circuit is indicated. Good circuit continuity measures less than 5 ohms with the VCM and sensor disconnected. Measure between the VCM connector and the HO2S connector. Ensure VCM terminal contact is good.

****Taken from Blazer Forum (blazerforum.com/forum/showthread.php?t=36730 (http://www.blazerforum.com/forum/showthread.php?t=36730))