Service Engine but no code?
10-05-2010, 09:42 PM
#13
TECH Enthusiast
Try doing a scan when the light is on and leave the engine running. The cheap scanners use what is called Global OBD II protocol. It will usually pick up any current DTC info. Many do not show history.
10-06-2010, 11:19 AM
#14
If the light has constant 12v and the PCM turns it on by grounding it, then a short on the ground side of the circuit would leave the light on at all times with no codes...I've seen this happen on Toyota's in the past. Not sure if the GM MIL works the same way though. As mentioned, if it's a manufacturer specific code though, the generic AutoZone scanner won't pick it up...
10-06-2010, 10:00 PM
#15
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There are P, U, C and B codes. Yours could be an Enhanced Code(manufacturer specific). All manufacturers have enhanced codes as well as generic ones which are required by the OBDII EPA mandate. If you're going to fix cars and trucks you need a decent scan tool. You can get a good PC based scan tool for a few hundred dollars these day. Most handheld units are very limited even though the TechII is handheld and costs thousands. If you work on GM TechII is the way to go. GM is phasing out the TechII and will soon use PC based.
10-07-2010, 01:03 AM
#20
That's the way my 2001's are also. Some of the newer GM's have a light on the dash that shows an engine with a wrench next to it, and it stays on while driving (after the message center goes out.)
I can't tell you how many customers brought their cars in for "check engine lights" that were actually "change oil lights", so I thought I'd ask. Apparently not the case here.
I can't tell you how many customers brought their cars in for "check engine lights" that were actually "change oil lights", so I thought I'd ask. Apparently not the case here.