Probelms with o2's
 

P0133 P0153 P0155 P0135 keep comming up. the eng sen fuse blew also (20) on the smaller fuse box under the hood. it powers the MAF so i connected a jumper wire stright to the MAF and bypassed everything in the harness. It also powers the heters in the o2's reverse lockout and brake switch. Checked the wiring everywhere and nothing is burnt or damaged. the o2's just wont heat. they work after the exhaust heat heats them up. but they dont stay hot. if ia let the car idle for a long time they cool off and quit working again. can anyone help me out? this all happened after hooker LT's went on. anyone know where everything runs so i can fix this problem?

Re: Probelms with o2's
 

TTT

Re: Probelms with o2's
 

P0133 Heated Oxygen Sensor (HO2S) Slow Response Sensor 1

Circuit Description:

The PCM continuously monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During the monitor period the PCM counts the number of times that the HO2S responds from rich to lean and from lean to rich and adds the amount of time it took to complete all transitions. With this information, the PCM can determine the average time for all transitions. If the average response time is too slow, a DTC will set.

The PCM determines the lean to rich transition when the HO2S voltage changes from less than 300 mV to greater than 600 mV. The PCM determines the rich to lean transition when the HO2S voltage changes from more than 600 mV to less than 300 mV. An HO2S that responds too slowly is most likely defective. Replace the HO2S.

Diagnostic Aids:

*This diagnostic only runs once per ignition cycle.
*A malfunction in the HO2S heater circuits causes a DTC to set. Inspect the HO2S heater circuits for an intermittent open or for a poor connection.
*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.
*When DTCs P0133 and P0153 are set at the same time, it is a good indication that a fuel contamination condition is present.
*An exhaust leak 6-12 inches away from the HO2S can cause a DTC to set.
*Certain RTV silicone gasket materials give off vapors that can contaminate the HO2S. There is also a possibility of silicone contamination caused by silicone in the fuel. If the sensors appear to be contaminated by silicone and all the silicone sealant is a non silicone base, advise the customer to try a different fuel company.

These are excerpts from the service manual. Good Luck!

Re: Probelms with o2's
 

the heaters dont work tho. it grounds and blows a fuse. you got a diagram of where the eng sen runs under the hood? the fuse that powers the MAF, break circut and o2 heaters?

Re: Probelms with o2's
 

Heater circuit is for o2's to get to operating temp quicker. Started after lt install? Any o2 wires damaged , o2,s damaged wires spliced anything? If not you can check with new fuse & disconnect 1 at a time till it stops blowing fuse. there is a better way of checking for this but giving you the easist dyi .

Re: Probelms with o2's
 

all the o2 power wires are fine. remember that there is more then o2's heaters on that fuse. i just dont know where they run. the MAF, brake switch and reverse lock out.

Re: Probelms with o2's
 

TTT

Re: Probelms with o2's
 

Heated Oxygen Sensors Operation

FRONT SET:

The Heated Oxygen Sensors are mounted in the exhaust system where they can monitor the oxygen content of the exhaust gas stream. The oxygen present in the exhaust gas reacts with the sensor to produce a voltage output. This voltage should constantly fluctuate from approximately 100 mV (high oxygen content = lean mixture) to 900 mV (low oxygen content = rich mixture). The heated oxygen sensor voltage can be monitored with a scan tool. By monitoring the voltage output of the oxygen sensor, the PCM calculates the fuel pulse width command to give to the injectors (lean mixture/low HO2S voltage = rich command, rich mixture/high HO2S voltage = lean command).

REAR SET:

To control emissions of Hydrocarbons (HC) , Carbon Monoxide (CO) , and Oxides of Nitrogen (NOx) , a three-way catalytic converter is used. The catalyst within the converter promotes a chemical reaction which oxidizes the HC and CO present in the exhaust gas, converting them into harmless water vapor and carbon dioxide. The catalyst also reduces NOx, converting it to nitrogen. The PCM has the ability to monitor this process using the Bank 1 HO2S 2 and the Bank 2 HO2S 2 heated oxygen sensors. The front HO2S sensors produces an output signal which indicates the amount of oxygen present in the exhaust gas entering the three-way catalytic converter. The rear HO2S sensors produces an output signal which indicates the oxygen storage capacity of the catalyst; this in turn indicates the catalysts ability to convert exhaust gases efficiently. If the catalyst is operating efficiently, the front sensors will produce a far more active signal than that produced by the rear sensors.

The catalyst monitor sensors operate the same as the fuel control sensors. Although the Bank 1 HO2S 2 and Bank 2 HO2S 2 sensors main function is catalyst monitoring they also play a limited role in fuel control. If a sensor output indicates a voltage either above or below the 450 millivolt bias voltage for an extended period of time, the PCM will make a slight adjustment to fuel trim to ensure that fuel delivery is correct for catalyst monitoring.

Re: Probelms with o2's
 

There's 4 different circuit descriptions under the ENG SEN fuse -

*Heated Oxygen Sensors
*Manual Transmission
*MAF sensor
*Stop Lamp Switch

Even though the O2 sensors may look ok, one of them could still be bad - just try what wrencher said - disconnect one at a time until the fuse stops blowing.

Re: Probelms with o2's
 

I get this problem on lots of cars . Your lucky it's constantly poping the fuse & it's not an intermittant problem those are fun! Usually when engine sense fuse has a problem it's the o2's. Just remember low resistance in a circuit= high amperage & thats why a fuse blows . You can check o2 heaters with an ohm meter.

Re: Probelms with o2's
 

I have inspected the complete harness except for the part that runs along the bell houseing. there is power to the front 2 but none to the rear 2. the ground is somewhere after the front o2's but where? anyone know where the stop lamp wire runs? in the car or outside? is it somewhere it can be burnt?