Skip the auto shop - Our mechanics make house calls

Q: Check engine light on.

asked by on

I have a 95 I6 4.9L with a check egine light on (turns on and off speratically). I had a guy scan with a computer and got a P0171, and another evp ept voltage low. I bought and changed the O2 sensor, as well as the canister purge valve (w/new hoses), per advice. I then figured out how to run the on board EEC-IV using the CIL and got codes: 327 Electronic pressure transducer (EPT)/differential pressure feedback exhaust (DPFE) sensor/electronic vacuum regulator (EVR) 522 Neutral/drive switch (NDS) 512 Keep alive memory (KAM) fault 111 All systems OK Replaced both battery terminal ends and a new battery. I've checked EGR Vacuum Solenoid for carbon buildup, but was clean. Intake manifold, throttle body gasket replaced. I have checked all other hoses for a vac leak using a can of starting fluid but all seems fine. Not to sure where to go from here. Thanks in advance for your help

My car has 268000 miles.
My car has a manual transmission.

A: The testing you did using the CIL may not h...

The testing you did using the CIL may not have been done correctly. During these tests you will need to cycle the clutch and accelerate the engine when the separator codes were received. This is done with a superstar 2 or NGS tester or equal. The test without a proper tester may not work correctly. The code 327 may be a good code but the others may not. I suggest having the DPFE checked using pinpoint tests with a vacuum pump to see if the EGR valve sticks when opening. If the valve sticks, and then pops open can cause the code. I recommend having a certified technician scan the computer for codes and inspect the vehicle in person in order to have this accurately diagnosed and repaired.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: transmission

Hi, thanks for writing in. The transmission in these vehicles have a problem where the bore to the servo that controls gear changes gets worn and binds the valve shaft. The transmission will need to be overhauled, the bore for...

Q: evap

Restriction in the EVAP vent or purge hoses can also cause this code. A restricted EVAP canister will also set P0446. A smoke test can find restricted canister. I suggest having a mechanic come out and diagnose your Check Engine...

Q: Bad Purge Valve?

Hey there. All modern cars are equipped with an Evaporative Emission Control (EVAP) system. The EVAP system prevents fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system collects and temporarily stores the fuel vapors in...

Related articles

How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.