VetteMan1989

went to advanced auto because the check engine light came on and the vette was running bad, died at stop sign. pulled up a code 34(map sensor voltage to low). vette has been hard to start and running bad at start up. according to haynes manual the map sensor is bad. if I replace it could someone tell me the voltage the sensor should have. I think it's .54 volts for a 1989 vette

86PACER

.54 volts is for the TPS (Throttle Position Sensor) mounted on the side of the throttle body. That is totally different and has nothing to do with your code 34. The MAF is the big round thing between the airbox and accordion air duct.

Check the connector and wires at the MAF sensor. The MAF also has two relays mounted on the firewall behind the battery. One is the MAF burn off relay and the other is the MAF power relay. The wire insulation on these can shrink back causing the bare wires to touch, so check for that too. Both relays are the same part# and are inexpensive.

Buying a MAF should be your last step because they are very expensive. If all else fails, hunt down a used MAF to swap in and see. You can get one off a Camaro. I don't think the parts people will allow you to swap theirs in without you first buying it. Some places won't accept returns on electical parts either.


Here's how to pull your own codes, and what each code means.

http://corvettebuyers.com/c4vettes/ecm.htm

Just bend a paper clip into a "U" shape.

I would also highly suggest you buy the original GM shop manual for your '89.

VetteMan1989

thanks for your help, I will take all of your information and use it.

AGENT 86

http://members.shaw.ca/corvette86/Code%2034.pdf

89 Bob L

Check all of the connections before doing anything. There are three main connections; 1- at the MAF, 2&3 - at the relays behind the battery. Disconnect the connections and make sure wires are not frayed or touching. Next, check the connectors to ensure tight fit. Then spray the connectors with some electric connector cleaner.

Check the link for additional info

http://members.shaw.ca/corvette86/Code%2034.pdf

vinnies87

Also the 2 relays on the firewall behind the battery, same #'s, about $13.00 ea, and the relays going usually throw that code...

VetteMan1989

I cleaned the thottle body and replaced the maf relays and all is well. No codes. Thanks for the help.