Computer keeps showing codes 13 (O2 sensor), 17 (Spark reference signal) and 58 (theft deterrent system).

Cleared codes with Autoxray scanner, slowly, one at a time they return in no particular order. Scanner said code 17 was caused by Cam sensor so replaced that along with a second replacement of a new O2 sensor.

Still throws codes and often won't hot restart.

Does anyone know if this code complex is due to a single problem? Have owned her since new (211,000km), never in accident, no wiring problems except 4 alternators. Finally switched from AC Delco to Bosch after warranty over & no dead alternators since.

All grounds in engine compartment & at computer seem good.

Any thoughts? Please!!!

Well, your spark reference signal comes off the CRANK sensor, not the cam sensor. The cam sensor determines fuel injector timing. You have the single-wire O2 sensor on a 92, so I'd trace that wire back, but make sure you're using an AC Delco O2. We've had bad luck with alot of other brands, particularly Bosch. For some reason, the 'others' just can't handle the high heat levels between the rear manifold and firewall.

I'm a victim of the Bosch O2 sensor. Lasted less than 30 days.

Your theft deterrent system is PROBABLY a broken cable from the trunk tumbler tamper-switch. It'* under the carpet in the trunk LID. If you disconnect the 2-wire white connector, I bet you'll be ok.

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Thank you for such a prompt reply.

Sorry about the confusing wording regarding Bosch above.

The new oxygen sensor is an AC Delco 02. As soon as engine warmed above 140 threw a 13 code after the new AC Delco sensor was installed.

The spark reference signal comes from the ignition module. Code 17 could be a faulty ignition module or wiring between it and the PCM. Need a diagnostic per the service manual.

2 oxygen sensors? A diagnostic may prove that your PCM is going bad. I would stress a good diagnostic for both of these problems.

The code 58 happens when the PCM loses the fuel-enable signal while running. This can happen if the resistor pellet in your key does not make good contact while the engine is running.

Do you own that scantool, or borrow it? I have an Actron that will work on your car. Might be a good idea to tap the data stream and see what else might be screwy. In a pinch, we could swap PCM'* and see what happens.

You may have seperate problems, but they may be inter-related, too.

Wow willwren, thanks for the offer.

I don't own the scantool, just rented it.

1) Still keeps throwing code 13 despite new AC Delco O2 sensor. Will try relacing wiring between sensor & PCM this weekend if I get time.

2) Now that weather is cooler, not getting code 17 very often but my wife had one day last week sitting in supermarket lot >1 hour because no start. She'* NOT HAPPY!!Obviously Cam sensor was not the problem. Have ordered AC Delco Crankshaft position sensor. Any tips on alignment at installation?

3) No code 58 since disconnected tumbler tamper switch. It would sometimes go weeks though before throwing a 58. Is there anything can be done to repair the switch if that was it?

I just pull the codes by shorting the terminals at the underdash connector. Real pain.

I think your scantool gave you the wrong diagnostic for the code 17. Where did you disconnect the wiring to the tumbler? I am not aware of a tamper switch in the tumbler. As a matter of fact, if you disconnect the leads to the ignition pellet sensor, the car will not start unless you have Code 58.

I'm afraid you're right about the scantool.

Disconnected the trunk tumbler tamper switch at the lock in the trunk. (see post #2)

Finally got the SES to stay out with no new codes set.


1) Code 13 Replaced the O2 sensor 3 times (2 were AC Delco). continued to throw code. Spent several hours tracing & replacing wiring. Finally found a bad ground between PCM & steering column. FIXED IT!!!!

2) Code 17 Despite the Autoxray scantool clearly stating that this code had been set by a defective Cam sensor, replacing that did not stop the code. Replacing the crankshaft position sensor did. DO NOT BUY THE AUTOXRAY SCANTOOL (at least the $200 one) for our vehicles.

3) Code 58 Disconnecting the trunk tumbler tamper switch did not stop this code. Has not recurred though since fixing the ground in 1). This code was sporadic though & it may return.