This 1997 Chevrolet S10 Blazer cam in with the service engine soon light on and a complaint of low power. Checked data with Tech 2 scan tool and found codes P0102 MAF sensor circuit low frequency and P0340 cam position sensor circuit. I checked CMP retard and found it fixed at -60 degrees. I talked with the customer and found that the distributor had been out for some other repairs. Sounded like the distributor (cam sensor is built into it) needed to be set. Removed the distributor, reindexed the rotor and installed. The engine ran but I could tell the timing was way off and strangely the cam retard was still at -60 degrees. I put the distributor back to where it was originally and started doing some research.
I found a case where the ENG-1 fuse was blown causing the same thing.
I checked the fuse.
Sure enough it was blown and replacing it corrected both codes.
CMP retard also reset to -7 degrees. A little off but within allowable specifications. Perfect would be 0.
Now what caused the fuse to blow. Kind of strange that there is a new fuse just below the
ENG- 1. What is that for?
The radio of course. Some one in the course of trying to keep a piece of junk radio installation going pulled the ENG-1 fuse, put it in place of a blown radio fuse and put the blown fuse back in the ENG-1 fuse holder . Blew again and decided to buy new fuses but never bothered replacing the ENG-1 fuse. Recommended having the radio properly wired but the customer declined at this time. No surprise!!!
THE ENG-1 FUSE WAS BLOWN ON MY 1998 SILVERADO CREW CAB, REPLACING THE 20 AMP FUSE FIXED BOTH OF THOSE CODES PO102 AND PO340 THANKS FOR LISTING THAT FIX
MARK
Glad the info could help you. Have to wonder why the fuse was blown though. As far as helping me the re is a way through the link at the top of the site page. It is marked “How To Thank Sparky?”
man i cant thank you enough. Replaced maf sensor and the cam sensor and was at store tonight looking for timing belts. i read this and ran right out and sure enough eng1 fuse was blown on my 97 suburban. put new one in and idle smoothed out powers back and no hesitation. check engine lights went off to. Wish i could buy you a beer cuz you just saved me a bunch of time and money. thanks
i change cam sensor then i read this and it fixed it thanks for the info. you saved me about $300
yes sirr i am so haooy it work on my 1999 gmc yukon 5.7 no codes runs great eng. 1fuse under hood blown that meant crank fuse in truck had no current ireplaced evrything before that mass sensor spider dist crank sensor plugs ac delco wires oil change fuel pump. cleaned egr. gas and air filter. cleaned pcm connections also daytime running lights are working again cheap hids the problem. thanks alot i can drive to my new job now 25 miles going and 25 on return.