2001 Buick axle shaft

[Bravada96]

Will a bad axle shaft cause the service engine light to come on? Car has service vehicle, abs, and trac off lights as well, but I know they are on because drivers side hub needs changed. The service engine light came on and I'm not sure why. I plan to take it to see if codes come up but haven't yet.

[gmtech1]

Originally Posted by Bravada96

Will a bad axle shaft cause the service engine light to come on? Car has service vehicle, abs, and trac off lights as well, but I know they are on because drivers side hub needs changed. The service engine light came on and I'm not sure why. I plan to take it to see if codes come up but haven't yet.

No, it will not cause and service engine soon light and will not set ecm/pcm codes. If it has a external tone ring that the speed sensor read, and that ring is damaged, it will cause a ABS light though...get the codes checked.

[Tech II]

Have the codes scanned for free at a place like Autozone....

[Bravada96]

Had codes read at Advance. There were 3, catalyst efficiency below threshold bank 1, engine oil pressure switch, and the one I knew which is front drivers wheel speed sensor. I'm wondering if it's ok to drive with a bad oil pressure switch until I can get one? Also from what I'm seeing online there's no way to know if catalyst code is the o2 sensors or the cat itself which sucks.

[Blue Bowtie]

You can test the O² sensor output in a propane flame. If it makes close to 1V after being heated lean, it is probably O.K.

As for the pressure switch, if a mechanical gauge is connected and oil pressure is acceptable, I wouldn't lose any sleep over the switch until it can be replaced.

[Carwhiz]

You can take car to a shop for a diagnostics to better assist your codes. With a GM TECHII scantool, they can monitor your O2 sensor readings to better assit you. OR, rather than paying them $100 bucks to do so, you can spend $60.00 on a set of Denso oxygen sensors. My decision would be to put in a fresh set of sensors, to see if that was the problem. Sensors are 15 years old anyways, unless they have been replaced since car was new.

Keep in mind, the PO420 OBDII code is a GENERAL catalyst malfunction, and there are NUMEROUS things that can actually cause this code. The catalyst converter is DESIGNED TO LAST INDEFINITELY, but they do fail typically due to other mechanical issues.

Oil pressure switch on the 3.1L engine is an electronic sending unit that sends a signal to the ECM. When ECM determines the sensor is not withing specs, it give you the SES light. Typcially the seal fails in these sensors, and therefore oil leaks into the electronic portion of these switches, shorting out their signal. This sensor is located on the front side of block, just above the starter. You can buy a new one for $15.00. I would say this is an easy price to attempt clearing up your SES light.

[Bravada96]

Yeah I plan to change the oil pressure switch myself. I also plan to look at the O2 sensors to see if I can replace them myself. If it turns out to be the converter I may even try to replace it myself to save a few bucks.

[Bravada96]

Does anyone know what the torque specs are for the oil pressure switch and o2 sensors for a 2001 Century?

[Blue Bowtie]

The oil pressure sensor uses tapered pipe threads, so a wrap of PTFE sealant tape will help prevent leaks and slightly lubricate the threads. Very little toques is required to seal, likely 5-8 ft/lb.

The O² sensor uses a seal washer, much like some spark plugs, so torque is also relatively low. It is more important to lubricate the threads. Most sensors are shipped with a coating of anti-seize compound applied to the threads, but it is barely adequate. Applying additional anti-seize and brushing it well into the threads is helpful, but use care so that none of the compound gets on the sensor tip.

[Bravada96]

I was wondering with the catalyst efficiency below threshold bank 1 code could be caused by the following: When I took car to the garage to originally get fixed, the pipe that comes from the cat and bolts to the exhaust pipe had separated. The garage welded it. If the weld didn't seal, could that cause it to throw that code?

[Blue Bowtie]

Air leakage upstream of the sensor will skew the readings, and if the reading is out of the acceptable range the code can set.