Mechanics

ENGINE LIGHT, EGR SYSTEM FAILURE

1995 Nissan Hardbody • 4 cylinder 2WD Manual • 195,000 miles

The engine light comes On in sporadic ocassions, mostly when driving over 50mph for long periods. I took it for scan and the code p32 showed up. I have replaced myself the two EGR valves and most of the hoses. After the replacement of valves the RPM niddle went down from over 2 to under 1 when is in neutral as it was before when the truck was new. The replacement, however, didn't solve the problem with the engine light. I replaced the EGR solenoid and the light didn't come ON for two days, but now has started to come ON and Off as it was before. By the way, the EGR sensor was replaced about a year ago. Practically the whole components of the EGR system are new. What I must do next? How to make the engine light to stop continuing coming ON and Off? It may be a loose connection somewhere?
Avatar
Nissanfun
March 23, 2011.




Go through the following and see if you can come up with anything.

DTC 32 - EGR FUNCTION
NOTE: DO NOT perform this test if DTC 12 is present.

1. Check Vacuum Source To EGR Valve

Start engine and warm to operating temperature. Disconnect hose from EGR valve and check vacuum. Vacuum should not be present. Raise engine speed to about 2000 RPM and check vacuum. Vacuum should be present. If vacuum not as specified, go to next step. If vacuum as specified, inspect EGR system. Repair or replace as necessary.

2. Check Control Function

If vacuum is not present at about 2000 RPM, measure voltage between ECM terminal No. 105 (White/Blue wire) and ground. See Fig. 2 and Fig. 24. At idle, voltage should be about zero volts. At 2000 RPM, voltage should be battery voltage. If voltage is not as specified, go to next step. If voltage is as specified, inspect vacuum hose for clogging, cracks or proper connection. Repair vacuum hose as necessary.

3. Check Power Supply

Turn ignition off. Disconnect EGRC solenoid valve wiring harness connector. See Fig. 23. Turn ignition on. Measure voltage between harness connector terminal "B" (Black/White wire) and ground. See Fig. 25. If battery voltage is not present, check wiring harness and harness connectors. Repair or replace as necessary. If battery voltage is present, go to next step.

4. Check Output Signal Circuit

Turn ignition off. Disconnect ECM harness connector. Check continuity
between ECM terminal No. 105 and EGRC solenoid valve wiring harness connector terminal "a" (White/Blue wire) See Fig. 2 and Fig. 26. If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.

5. Check Component

Inspect EGRC solenoid valve (On California models, measure resistance of EGR temp. Sensor). Repair or replace components as necessary.


KHLow2008
May 31, 2011.
Thank you for your reply.

I found the cause of the problem. It happened that on December last year the pulley for the steering wheel stopped running and the belt did burn and broke up. I had a hard time driving the truck but I managed to reach home. I bought a new pulley and a new belt and that was the end of the story.

Two weeks later, the engine light started to come On and Off in sporadic events, specially when I was driving over 50mph. I took the truck to the mechanic for a full inspection, and a list was made for repairs needed. About the engine light, the code was p32, that involved the EGR system. He suggested to clean and or repair the valves. I did some mistakes, like letting the cleaner to wet the diapragm of the EGR valves, and as a precaution I replaced them. When I tried to check the EGR solenoid, I broke one of the plastic pipes and I also had to replace the solenoid. After each replacement the engine light didn't show up for one or two days, but later started to come On for a while.

So, after doing the electrical inspection followimng the directions of the shop manual, I decided to clean up the intake manifold, believing that perhaps carbon accumulation was the problem. After I studied how to remove the whole parts to reach the manifold body, and taking pictures and adding labels to wires and etc, I decided to take a last view of the hoses. I had replaced all the hoses around the EGR valve, but at this time, as a "just in case" measurement, I decided to replace also the hoses going to the carbon canister and the solenoid EGRC, located on the other side of the motor. I made this last attempt trying to save lots of work to clean up the manifold.

To my surprise, the hose going to the carbon canister had a big long and wide cut. It happened that when the steering wheel broke up, also made a huge scratch to this hose, but as it did it on the bottom of it, neither me, neither the mechanic was able to see it. From any inspection the hose should pass as OK, and only by removing it I was able to see the big cut, it was practically a long hole. The location of the cut was right where the hoses are hold with a clamp in front of the radiator.

I replaced the broken hose, rised up the seat, followed the steps to clean up the codes in the ECM, check the ECM after that, I received the 55 code and made the road test. No more problems with the engine light.

I can tell that this experience was useful after all, I have learned a lot about the EGR system and how to read codes without a scan tool (saving 50 bucks).

I never related the broken steering wheel belt with the showing up of the engine light, because it came On two weeks later and since then was acting crazy. At least I know now that a hole in this hose will cause such a weird behavior with the engine light and code p32.

Thanks again for your answer, and next time I will go further than a visual inspection if a similar problem comes with this truck or with my other vehicle.

My best wishes.
AD


Tiny
Nissanfun
Jun 2, 2011.

AD