Ask the Auto Doctor
Q: I have a 2007 Dodge Nitro. Sometimes a symbol on the dash (it looks like an electric bolt) comes on when starting the vehicle and does not go out right away, and then the vehicle will usually not start. We have replaced the Electronic Throttle Control Sensor twice. Sometimes when I turn the vehicle off and leave it for 15 minutes it will not start back up. It acts like it wants to start but it will not (almost as if it isn’t getting gas). When my husband lifts the hood and taps the sensor with something, it will start. A mechanic scanned it with a code reader, but did not get any reading whatsoever. The Dodge dealer kept it for a week, drove it, turned it off, let it idle, but it never acted up and they said they could not find anything wrong with it. Any advice? — Lan.
A: Today’s vehicles are loaded with electronics, and intermittent problems such as yours can sometimes not be found unless the vehicle is in a no-start condition while at the shop. We do not have a magic wand to fix these crazy vehicles, sometimes we get lucky and find the problem with a simple connection wiggle test. Switch the key to the “on” position without turning it to the start position to “retrain” the key and see if the problem might be with the anti-theft system.
Q: I have a 2004 Ford Escape 2.0-liter with 300,000 miles. It’s showing code P0401 problem in the EGR system. I have replaced the EGR valve, the vacuum regulator, and the pressure feedback sensor. When the vacuum hose is connected from the vacuum regulator to the EGR valve, the engine idles rough and almost shuts off, but when I disconnect the vacuum hose from the EGR valve, the engine idles fine. I put a vacuum pump on the EGR valve and pumped it up, but there was no change in the idle. It is still showing code P0401. Where do I go from here? — Rick
A: The EGR valve should not have any vacuum going to it at idle. EGR valves usually do fail on these engines. Plugged passageways in the intake manifold are the most common problem. EGR valve operation is electronically monitored, and a code will be triggered if it does not open or drop in vacuum. Both Alldata and Identifix have a trouble flow chart for step-bystep diagnosis.
Q: I have a 2008 Chevy Colorado that has developed a pass-lock system problem. It’s happened on two occasions where I have to wait 10 minutes before it will crank and start. What is the proper way to fix the problem? — Ed.
A: The reason you have to wait 10 minutes to start the engine is because the antitheft module has lost communication with the ignition key. You need to start the vehicle with a replacement key and clear the computer body control module codes. This should be the only step needed; if this fails then you will need to take the truck to the local dealer or qualified shop that has a factory scan tool.
Junior Damato is an ASEcertified Master Technician. Email questions for publication to info@ motormatters.biz