I got a code E048, EGR System Fault trouble code on my '89 eldorado, after about 30 minutes of highway driving.. it stays on now..even after i clear the codes, it comes back.. how do i go about testing whether the EGR valve is bad or if the solenoid is bad? Im not familiar with using the caddy diagnostics to troubleshoot problems

I got a code E048, EGR System Fault trouble code on my '89 eldorado, after about 30 minutes of highway driving.. it stays on now..even after i clear the codes, it comes back.. how do i go about testing whether the EGR valve is bad or if the solenoid is bad? Im not familiar with using the caddy diagnostics to troubleshoot problems

It may only need cleaning and calibration. Use the search feature for "clean EGR". EGR system fault can be one of many little snakes, but normally it is a simple fix.

It may only need cleaning and calibration. Use the search feature for "clean EGR". EGR system fault can be one of many little snakes, but normally it is a simple fix.

i dont see how the egr system will clean itself.. that makes no sense.. am I amissing something here?

Clean the tubes inside throttle body and you will get rid of code but still may be not good for emission test.

Clean the tubes inside throttle body and you will get rid of code but still may be not good for emission test.

this did nothing to help the code.. it still sets itself.. anybody have a test procedure for the egr solenoid?

this did nothing to help the code.. it still sets itself.. anybody have a test procedure for the egr solenoid?
The easiest way to test the EGR solenoid to replace it with a new one. If it does not help, just return it. Replacing takes some 30 seconds. This subject was discussed a few months ago, search the archives for the procedure. You will need a vacuum gauge. You will most likely end up replacing the EGR valve.

I just looked up the Service Information Manual for E048 - EGR System Fault. The manual gives you a detail Flowchart Troubleshooting procedure to exactly pinpoint what is the cause - a faulty solenoid, EGR unit, leak or obstruction etc... and also a section on how to use the CCP and how the EGR control process work If you cannot find the manual in your library I will be happy to copy the flowchart and send you a copy.

Try buying a Service Information Manual from eBay (approx. $20 - $30) for your car, worth every penny that you will invest in the manual.

GT8888