codes 15 and 32

[c/kman]

Hey guys I've got a '91 C1500 with 160,000 miles on it and it's been shooting the 15 and 32 trouble code over and over for about 2 months. Finally about two weeks ago I was on my way back from school and the truck had a real rough idle and it would stagger/stumble as I would try to accelerate. I did'nt hink I was even going to make it home but thankfully I made it. After that I replaced the egr valve but it had no effect. The truck has been sitting for about a week now and I was hoping that y'all could help me get back in my truck( I am starting to miss her) Please if anyone has any ideas let me know I would appreciate it.

[2000CAYukon]

http://www.troublecodes.net/GM/89-90_57k.shtml

15 says the ECT sensor is reporting a low temp even after the engine has been running for a while. Make sure it is still connected. Also verify that the grounds on the intake are still good.

32 says that the when the EGR was commanded on, there was no change in the MAP sensor. This could be EGR valve, EGR solenoid, vacuum issue to the solenoid/egr valve or electrical to the EGR solenoid. It could also be a blocked EGR port in the intake manifold.

//2000CAYukon

[c/kman]

I looked at the switch and it's still plugged in and the ground still looks good and I put in my brothers egr solenoid( he has the same truck) and still runs like s***. Thanks for the info though.

[c/kman]

bump

[c/kman]

Any other suggestions/ideas

[777stickman]

Originally Posted by c/kman

Any other suggestions/ideas

I have a suggestion. Post back when you have checked everything that 2000CA Yukon suggested.

[c/kman]

Wow, Thanks 777stickrider that was great help!!!! I already looked at what he told me and it was neither. I also replaced the Engine coolant temperature sensors and nothing. Thanks again 777stickman you are very helpful.

[c/kman]

bump

[c/kman]

Any other suggestions/ideas

[c/kman]

morning bump

[2000CAYukon]

Code 15: Most likely the sensor is bad; however, it could be wiring. Using an ohm meter, read the resistance of the sensor when the engine is fully warmed up. Should be around 200 ohms. If greater than 1000 ohms, it should be replaced.

Code 32:
1) Need to make sure the manifold side of the EGR solenoid is getting vacuum.
2) With Diag Terminal grounded (Pins A and B), Ignition ON, Engine OFF, make sure that the vacuum is seen on the EGR side of the solenoid when a vacuum pump is used on the manifold side. If not, the EGR solenoid should be replaced.
3) Diag Terminal grounded, Ignition ON, Engine OFF, apply vacuum to manifold side of EGR solenoid, EGR valve should move. If EGR valve does not move, apply vacuum directly to EGR valve and make sure if moves. If not, replace the EGR valve.
4) Engine running, push the EGR valve by hand, idle should get rough, if not, the EGR passage is blocked and needs to be cleaned out.

//2000CAYukon

[c/kman]

Alright, I'm going to give that a try a.s.a.p, but it may not be until friday or so, but I want to thank you very much for your input and I'll get back to you and le you know what happens. Oh and about the engine coolant temp sensor I already replaced it with a new one from Auto zone and no change. It still idles rough, is there a possibility that the new one might be bad? Again thanks for your quick response

[2000CAYukon]

Just to be clear the ECT sensor is in the intake manifold. The one in the cylinder head is for the gauge.

If you replaced it, did you clear the code to see if came back? You can clear the codes by disconnecting the battery for 10 - 15 minutes.

A bad EGR valve can cause a rough idle. On my 90 K1500 5.7L, my rough idle was caused by a bad PCV gromet. The gromet was hard and no longer sealed causing a vacuum leak.

Since you have a code 32, you need to find out what is causing the code 32.

If the code 15 comes back, you need to see what the sensor value is (OHM meter) and if it is in spec, it could be a wiring or ground issue.

//2000CAYukon

[c/kman]

The ECTsensor on top of the intake manifold is the one I replaced but I only disconnected the battery for about a minute. You say it takes 10-15 min. I'm going totry that and see what happens, it's just that I've been real busy with school and haven't been able to get around to putting the voltmeter to it. Thanks again for all of your help and patience.

[c/kman]

Alright guys so heres the feedback. Called up a friend that works for the county working on worktrucks (91,92,93,94 c1500's) Anyway he came over checked the EGR solenoid and the ECT with a voltmeter, everything seemed fine. So he says you know I think it's the fuel pump. I went out and bought fump pump put it in and BINGO!!!! Problems solved the truck is running great. I would like to thank everybody for their input and help.