I'm sure this has been posted before, but i'm getting an intermittent code 34, with 2 different MAF sensors installed, what are the probable causes?

 

Code 33 / 34 tests.

First check air ducts for cracks, holes and tighten clamps.

With the ignition off, unplug the MAF and apply power to ALDL terminal
"G". Check the red wire on the MAF connector for power. If no power,
verify 12v on relay connector orange and white/tan wires. Verify the
connector black/white wire is grounded. Verify black wire from MAF
connector terminal B to ECM connector A11 with an ohm meter. Verify
red wire from relay connector to MAF connector with an ohm meter.
If all is good replace MAF power relay.

Turn ignition on, Check MAF connector dark blue wire for 12v, if so,
unplug MAF burn off relay and check again. If so, check relay
connector black wire for ground. If so, the black wire is shorted to
ground or the ECM is bad. If not, replace MAF burn off relay.

If the dark blue wire at the start of the above test had no voltage,
check the MAF connector dark green wire with ignition on for a 5v
reference signal. If so, and all connectors are good, replace MAF.
If no 5v reference on dark green wire, verify it from the MAF connector
to ECM connector B12 with an ohm meter. If the wire is good replace the
ECM. If the dark green wire has 12v on it, turn ignition off and unplug
the ECM connectors. Turn ignition back on and check again, if so,
it is shorted to power somewhere. If not, and all connectors and
grounds are good replace ECM.

 

What year of car?

 

86

 

There is a service bulliten for that year of car, it deals with false code 34 (among other issues) It requires replacing the calpack and you have to pay for it, not GM. I chased this problem on my car about 15 years ago.

 

Morley,
It's a Corvette, does that make any difference?

 

I believe all of the TPI proms had the same problems, 1985 & 1986. Ask your GM techs point blank if there is a service bulliten for your application. I had to ask them because they were too lazy to think of it on their own and look it up.

 

bad maf relay?