Check Engine light is on, and mechanic's not helping

  • Article by: PAUL BRAND
  • Updated: September 14, 2012 - 4:04 PM
Q I have a problem with my 2005 Mazda 6. My "Check Engine" light came on so I went to the mechanic to have him pull the code. He said it wasn't really reading anything, reset the code and told me to come in if it happens again. The next day it came on again. I stopped at the gas station since I needed gas and filled my tank. When I went to start my car, it wouldn't start. I sat there for 15 minutes before it started. When it did start, I had to give it some gas because it was sputtering. The Check Engine light was still on so I brought the car to the mechanic the next day. He reset the code again and said to let him know if it came on again at the gas station next time.

I filled up about a week later and once again it wouldn't start. I told my mechanic this and he said to try to get gas with the car running next time. So once again I got gas but this time left my car running. This time, as I was pumping gas, the car was sputtering and the tachometer was fluttering the entire time. But when I was done pumping, it seemed to run just fine. My car acts up only when filling gas; otherwise it runs great.

A What's interesting about this question is that the mechanic is trying to pinpoint the problem by asking the car owner to do all the work! Try this, try that, etc. Since the Check Engine light has come on each time, a scan tool should identify the specific DTC fault code associated with this problem. The comment "wasn't really reading anything" doesn't make sense -- the Check Engine light was on!

I suspect the DTC will relate to the evaporative emissions system, which includes the purge valve. If the purge valve is stuck open, raw fuel/vapors can be pumped through the charcoal canister directly into the induction system during refueling, which, of course, would create exactly the symptoms you've described.

Q I have a 2004 5.7-liter Dodge Durango with 190,000 miles. As I come to a complete stop, the tachometer will drop momentarily from around 750 rpm to less than 500. The engine will occasionally stall. I must depress the gas pedal slightly to get it restarted. Initially I had the throttle body thoroughly cleaned, then replaced it this past weekend. I also replaced the oxygen sensors but nothing has helped. I should also mention that the Check Engine light has never come on. Any ideas?

A The 5.7-liter V8 in this vehicle is equipped with a "fly-by-wire" throttle system. Instead of a mechanical cable or linkage connecting the throttle pedal to the throttle body, an accelerator pedal position sensor (APPS) is fitted directly to the throttle pedal and electrically connected to the PCM (powertrain control module). In simple terms, rather than the throttle plate being opened and closed mechanically by movement of the throttle pedal, the position of the throttle pedal is communicated to the PCM, which operates the throttle via signal to the electronic throttle body.

Having both cleaned and replaced the throttle body, which includes the throttle and idle air control valve, I'd suggest plugging in a scan tool and having the APPS swept/checked for dead spots in its potentiometer. Also, check for any type of vacuum or air leak in the induction system that would allow un-metered air into system.

Q I had to replace the engine in my 2004 Chevy Aveo recently. Since I got it running again, the battery light on my dash is on constantly. I have had the alternator tested in and out of the car and still no answer.

A If the alternator is charging properly, look for a short to ground in the indicator light control circuit.

  • get related content delivered to your inbox

  • manage my email subscriptions

ADVERTISEMENT

NY Yankees - LP: M. Pineda 0 FINAL
Toronto - WP: D. Hutchison 2
Detroit - LP: M. Scherzer 3 FINAL
Chicago WSox - WP: C. Sale 6
Chicago Cubs 5 Top 7th Inning
St. Louis 1
Cincinnati 0 Top 1st Inning
Pittsburgh 0
Minnesota - K. Gibson 6:05 PM
Baltimore - C. Tillman
Philadelphia - J. Williams 6:10 PM
NY Mets - B. Colon
Miami - J. Cosart 6:10 PM
Atlanta - A. Harang
Boston - A. Webster 6:10 PM
Tampa Bay - J. Odorizzi
Cleveland - T. Bauer 6:10 PM
Kansas City - J. Shields
Detroit - K. Ryan 6:10 PM
Chicago WSox - C. Bassitt
Texas - R. Ross Jr. 6:10 PM
Houston - S. Feldman
Colorado - T. Matzek 7:10 PM
Arizona - V. Nuno
Chicago Cubs - T. Wada 7:15 PM
St. Louis - M. Gonzales
Los Angeles - Z. Greinke 7:40 PM
San Diego - I. Kennedy
Milwaukee - M. Fiers 8:05 PM
San Francisco - J. Peavy
Oakland - J. Samardzija 8:05 PM
LA Angels - C. Rasmus
Washington - S. Strasburg 8:10 PM
Seattle - R. Elias
Green Bay 9/4/14 7:30 PM
Seattle
BYU 35 FINAL
Connecticut 10
(6) Jacksonville St 7 FINAL
(8) Michigan State 45
Bowling Green 31 FINAL
Western Ky 59
TX-San Antonio 27 FINAL
Houston 7
Colorado State 31 FINAL
Colorado 17
UNLV 13 FINAL
Arizona 58
Penn State 26 FINAL
UCF 24
Troy 10 FINAL
UAB 48
(7) UCLA 28 FINAL
Virginia 20
Western Mich 34 FINAL
Purdue 43
(5) Ohio State 34 FINAL
Navy 17
Appalachian St 14 FINAL
Michigan 52
Ga Southern 23 FINAL
NC State 24
Boston College 6 2nd Qtr 4:03
Massachusetts 0
West Virginia 3 1st Qtr 3:47
(2) Alabama 3
Rice 0 1st Qtr 3:50
(17) Notre Dame 7
(10) South Dakota St 7 1st Qtr 6:15
(24) Missouri 21
Fla Atlantic 7 1st Qtr 4:15
(22) Nebraska 7
California 7 1st Qtr 1:00
Northwestern 0
Marshall 7 1st Qtr 4:20
Miami-Ohio 0
UC Davis 3:00 PM
(11) Stanford
Arkansas 0 1st Qtr 12:30
(6) Auburn 0
(16) Clemson 4:30 PM
(12) Georgia
Liberty 5:00 PM
(23) North Carolina
Ohio U 5:00 PM
Kent State
Louisiana Tech 6:00 PM
(4) Oklahoma
Idaho 6:00 PM
Florida
Stephen F Austin 6:10 PM
(20) Kansas State
Fresno State 6:30 PM
(15) USC
Southern Miss 6:30 PM
Miss State
Texas-El Paso 7:00 PM
New Mexico
North Texas 7:00 PM
Texas
(1) Florida State 7:00 PM
Oklahoma State
(14) Wisconsin 8:00 PM
(13) LSU
South Dakota 9:30 PM
(3) Oregon
(25) Washington 9:30 PM
Hawaii
Utah State 8/31/14 6:00 PM
Tennessee
SMU 8/31/14 6:30 PM
(10) Baylor
Miami-Florida 9/1/14 7:00 PM
Louisville
Arizona 9/4/14 7:00 PM
TX-San Antonio
Pittsburgh 9/5/14 6:00 PM
Boston College
Washington St 9/5/14 9:30 PM
Nevada
SMU 9/6/14 11:00 AM
North Texas
Fla Atlantic 9/6/14 11:00 AM
(2) Alabama
Buffalo 9/6/14 11:00 AM
Army
(24) Missouri 9/6/14 11:00 AM
Toledo
Arkansas State 9/6/14 11:00 AM
Tennessee
(8) McNeese State 9/6/14 11:00 AM
(22) Nebraska
Central Mich 9/6/14 11:00 AM
Purdue
Akron 9/6/14 11:00 AM
Penn State
Western Ill 9/6/14 11:00 AM
(14) Wisconsin
(20) Kansas State 9/6/14 11:00 AM
Iowa State
(4) Oklahoma 9/6/14 11:00 AM
Tulsa
Western Ky 9/6/14 11:00 AM
Illinois
SC State 9/6/14 11:30 AM
(16) Clemson
Navy 9/6/14 12:00 PM
Temple
UAB 9/6/14 1:00 PM
Miss State
South Alabama 9/6/14 1:00 PM
Kent State
New Mexico St 9/6/14 1:00 PM
Georgia State
Colorado 9/6/14 2:00 PM
Massachusetts
Fresno State 9/6/14 2:00 PM
Utah
(1) Eastern Wash 9/6/14 2:00 PM
(25) Washington
(15) USC 9/6/14 2:30 PM
(11) Stanford
Ohio U 9/6/14 2:30 PM
Kentucky
Middle Tennessee 9/6/14 2:30 PM
Minnesota
Northern Ill 9/6/14 2:30 PM
Northwestern
Missouri State 9/6/14 2:30 PM
Oklahoma State
Ball State 9/6/14 2:30 PM
Iowa
Maryland 9/6/14 2:30 PM
So Florida
Eastern Mich 9/6/14 3:00 PM
Florida
Georgia Tech 9/6/14 3:00 PM
Tulane
(18) Ole Miss 9/6/14 3:30 PM
Vanderbilt
Old Dominion 9/6/14 5:00 PM
NC State
(8) Michigan State 9/6/14 5:30 PM
(3) Oregon
(19) Arizona State 9/6/14 6:00 PM
New Mexico
Louisiana Tech 9/6/14 6:00 PM
Louisiana
San Jose St 9/6/14 6:00 PM
(6) Auburn
East Carolina 9/6/14 6:00 PM
(9) So Carolina
Duke 9/6/14 6:00 PM
Troy
Idaho 9/6/14 6:00 PM
ULM
(17) Sam Houston St 9/6/14 6:30 PM
(13) LSU
Michigan 9/6/14 6:30 PM
(17) Notre Dame
Lamar 9/6/14 6:30 PM
(21) Texas A&M
Northwestern St 9/6/14 6:30 PM
(10) Baylor
BYU 9/6/14 6:30 PM
Texas
Citadel 9/6/14 6:30 PM
(1) Florida State
San Diego St 9/6/14 7:00 PM
(23) North Carolina
Virginia Tech 9/6/14 7:00 PM
(5) Ohio State
Memphis 9/6/14 9:00 PM
(7) UCLA
Colorado State 9/6/14 9:15 PM
Boise State
Air Force 9/6/14 9:15 PM
Wyoming
Oregon State 9/6/14 9:30 PM
Hawaii
Texas Tech 9/6/14 10:00 PM
Texas-El Paso
Colorado 0 1st Half 44:55
Seattle 0
New England 4:00 PM
Toronto FC
Columbus 6:30 PM
Montreal
FC Dallas 7:30 PM
Chicago
Real Salt Lake 9:30 PM
San Jose
Portland 9:30 PM
Vancouver FC
Ottawa 10 FINAL
Montreal 20
Winnipeg 8/31/14 3:00 PM
Saskatchewan
Toronto 9/1/14 12:00 PM
Hamilton
Edmonton 9/1/14 3:30 PM
Calgary
Brt Columbia 9/5/14 6:30 PM
Ottawa
Calgary 9/6/14 6:00 PM
Edmonton
Hamilton 9/7/14 12:00 PM
Montreal
Saskatchewan 9/7/14 3:00 PM
Winnipeg
Chicago 6:00 PM
Indiana
Connect with twitterConnect with facebookConnect with Google+Connect with PinterestConnect with PinterestConnect with RssfeedConnect with email newsletters

ADVERTISEMENT

ADVERTISEMENT

ADVERTISEMENT

 
Close