I need your help guys. I have been scanning my car with the AutoXray scanner to get data for prom tuning. I have the 85 870 ECM. When I start scanning my idle goes up. According to the AutoXray manual "if the idle speed is affected during scanning then the ecm is in "Service Mode" and should not be driven. The "service mode" fixes the timing and idle speed. I had a long talk last night with Len from AutoXray. He said that there is no way around this and that all scanners will do the same thing including Snap-on and GM scanners used at the dealer. Is this true? Is the "service mode" the same as limp home mode? Do all scanners make the 870 ECM go into "service mode"? Is the data I have been taking for the last 6 months any good? How do I get data for prom tuning if I can't scan my car? Please let me know what you think and if you have scanned an 870 ECM with no problems what scanner did you use? Help!!!!

 

Moderator could you please move this to the ECM board as I have gotten no response from this board. Thanks

 

Got the same prob.. I have a '88 GTA with the 165 ECM. I don't trust the autoxray figures not to mention the MAF showing like 3200 grams/sec at idle instead of the normal of 6-9 or whatever g/sec.. I didn't realize it was kicking idle up and nearly missed a turn..