Help - ECM codes 22, 24, 34

[lovemonkeysd]

Hi,

I have a '90 SE and my check engine light is going on and off randomly. I've shorted the A&B terminals on the ALDL and got codes 22, 24, & 34. According to the ECM section on espritfactfile.com they are TPS circuit voltage low, Vehicle Speed Sensor Circuit, and MAP Sensor Circuit voltage low, respectively.

I reset the ECM and took it for a drive. The check engine light came back on and now the codes being thrown are just 22 & 34. Looks like I have a low voltage problem, but I don't know where to look.

Does anybody have any ideas where to start? Any web pages?

I appreciate the help.

[scotty2]

When I had trouble with MAP sensor codes I found it was all due to a split and perished rubber elbow and a cracked plastic adaptor for the pipe that runs to the MAP sensor. Its just like an old advance retard pipe off a distributor.

Find a little black plastic pipe (about 1-2 mm dia)that runs from below your charge cooler in the inlet manifold, then check it hasn't come adrift. Check the rubber elbow on the MAP sensor also. Its in the RHS rear butress and was a bit tricky to remove, but easier to put back !!

[lovemonkeysd]

Thanks for the info. I checked the pipe and rubber elbows and found no cracks or anything. In fact the rubber elbows are still very pliable and the pipe seems fine. You weren't kidding about getting to the MAP sensor -- sometimes I think you have to be about 12 inches tall to work on these cars. Just to be sure, the MAP sensor is right underneath the Boost Gauge Transducer and the Barometric Pressure sensor, right?

Any other ideas about what might be causing my intermittent check engine light?