: V will not start not power to ing/coil fuse

04-15-10, 11:29 PM
Ok the story is my V went in to limp home mode and I had not volts on the accelerator position sensor had a code D1125. The car would idle all day long but if you pressed the petal not changed. Changed the TPS and the APS and now the car will not start. Scan tool shows 0 codes and I had not spark so I started troubleshooting and found that the all the fuse terminals had volts that were suppose to have volts but 3: the odd ing/coil, post O2 and the even ing/coil. I took the fuse box out the see what was up but you cant get to the fuse terminals from the under side of the fuse box. Anyone have any ideal what could cause you to loose power to these 3 fuse terminals?

04-16-10, 07:16 AM
The ignition coil banks must have power or the car would not idle.

04-16-10, 08:27 AM
Thanks and I agree. The car would idle so I had power but something else has has happened and caused the no power to the fuses, which in turn is not sending power to the coils. I need help because the scan tool shows 0 codes and I can't understand how on three fuse term-blocks don't have power.

04-16-10, 09:16 AM
So you changed the TPS and the APP sensors? Now the car won't start? Don't they have to be recalibrated or sync'd after replacement? I thought I read about this on other GM vehicles also. I'm pretty sure the PCM makes sure the signals from these two coincide prior to allowing the vehicle to start, this may be why you're not getting any voltage. Darkman - we need the service manual procedure for replacing those sensors.

Side note - My old H3 used to go into limp mode because of APP to TPS errors due to water intrusion on an IP wire harness conneciton. Try getting that anemic pig up to highway speed while in limp mode. Literally took 1.25 miles to get to 65 mph.

04-16-10, 09:59 PM
See attached. I don't show a replacement procedure on the thottle position sensor - appears to be a simple unplug the old/plug in the new, but I just guessing.

04-18-10, 10:57 PM
How can you not have power to just 3 fuse blocks? Please someone tell me what I'm missing

04-22-10, 11:44 PM
Ok I have found out that it is the R49 Fuse Circuit that has no power which include the TOS, EMC, ODD INJ/COIL, PRE 02/CAM, POST 02 AND EVEN INJ/COIL fuses. R49 is given power by the Main Relay Micro. I bought a new one and still not power, I know the micro relay is good because I swapped it with the IGN 1 Relay Micro and all that circuit(R45) has power with either relay. I have power to the top passenger side terminal on the Main Relay Micro with the key off and when you turn the key on I have power to the both the top and bottom passenger side terminals. But no power to the 6 fuse in the R49 circuit. Does anyone know the instruction to take the under hood fuse box apart. It looks like I will need a new fuse box. Any thoughts?

04-24-10, 09:33 PM
What does the anti theft system do when triggered? I bought the car used and only have the #2 key less entry, could the anti theft system be why that circuit has no power? I ordered a service manual maybe I can determine the cause.

04-24-10, 10:09 PM
:thumbsup: on the Service Manual. See attached.