Engine cranks but does not start

JS20

MEMBER
2008 PONTIAC GRAND PRIX
3.8L
6 CYL
2WD
AUTOMATIC
170,000 MILES

I checked all of my fuses, all were okay. I then checked power to all of my fuses and the the following fuses aren't receiving power when the key is turned on: 12 (Emission), 14 (Oxygen Sensor), 17 (Electronic Throttle Control), 20 (Fuel Injection), 24 (Electronic Ignition). What could be causing this?

1 Reply

AL514

MECHANIC
4,098 POSTS

Hello, it looks like you're having an issue with the "powertrain relay". This relay is in the fuse block on the right strut tower in the engine compartment. The relay is activated by the PCM grounding the control side of the relay. So you either have just a bad relay or the PCM is not grounding it. it's relay #40. A quick check is to just swap out the relay, or if you own an automotive 12 volt test light you can hook the test to the battery negative and pull the relay out. You should have 2 pins with 12 volt power. If you have power on 2 pins, switch out the relay. They're not expensive, if that doesn't fix it then the PCM is the issue. It may have a bad ground or burnt driver for that relay. The first diagram will show you the power train relay. Let us know what you find.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-a-car-electrical-system-works

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

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