boostang321

Hey had my 09 hhr ss for a while now with little to no issues has 116k on it but recently went on some bump roads and very soon after that I ran into all kinds of issues think I might have a bad bcm. so car is very had to start now and reduced power is displayed also I have a slue of codes

p0193 frp sensor circuit high
p0463 fuel level sensor circuit high
p0234 turbo charger engine overboost
p0643 5 volt reference 1 circuit high voltage
p0642 5 volt reference 1 circuit low voltage
p0108 map circuit high voltage
p0106 undocumented code
p2227 baro sensor performance
p0238 turbo boost circuit high voltage

the fuel gauge shows low fuel even tho there is fuel in the vehicle
has no power what so ever any help would be appreciated

firemangeorge

Check all the battery connections and ground points. Sounds like the bumpy road has jarred something loose.
All modern electronic cars (HHR's included) are very finicky when it comes to battery voltage spikes.
Seen it before on this site where voltage issues will cause a "slew" of codes to show up.
I would start there.

Note: Bad BCM is doubtful. Seems like everyone wants to blame the BCM. It's usually because the BCM is not receiving a good connection or data.

boostang321

battery connections look good there tight I'm going to check the voltages with a meter to see if I'm getting a voltage drop somewhere grounds were tight and looked good also

firemangeorge

When I said battery connections, I don't mean just in the back at the battery. Up front at the fuse box, alternator and starter are other points to look at. The one at the fuse box is a known weak spot on the HHR.

Ground points. There's a bunch of those. Several under the hood can cause issues like you described.

Word of caution. Disconnect the battery if you go poking around under the hood. Several have learned the hard way that things are easy to short out under there.

Oldblue

Double check the load capacity on the battery, these trucklets don’t like a low voltage battery!

donbrew

Remove and reinstall the under hood fuse box. The connectors under it can get loose and the fuses get loose.

Check the large red wire at the under hood fuse box.

Check the connectors to the ECM.

Odd that you would suspect the Body Control Module for Engine codes. Who told you that?

boostang321

ok so here is the deal I did some simple checks on the car and everything checked ok did some research on alldata and found that these cars have 3 separate 5 volt circuits coming from the ecu and 1-3 power different sensors ect

so that being said I look into what exactly 5v reference controls some of the sensors I was having issues with and I found there all on 5v-1 these include

Map
fuel rail pressure sensor
clutch switch I know strange
baro sensor at fuel tank
intake air pressure and temp sensor

so I got my meter out check the easiest to get to was the map sensor found with key on I had less then a volt there check the other easier sensors to get to found they all had around the same less then a volt then I checked continuity to ground and it was high so wasn't suspecting a short to ground at that time. so hooked the solus back up to the car and ran back through the data list is shows all 3 5v signals in 2 states failed or ok 5v1 showed failed I kinda already knew this just a little double check. so at this point the only thing that hasn't been checked is the baro sensor at the fuel tank and the wiring harness it self if there was a bad sensor other then the barro I would have got my 5v back once unplugging the failed sensor this did not happen

so on to the issue I jack the car up I honestly don't want to drop the fuel tank on my driveway so I crawl under looking for wire damage of see if there is a connector visible. on the pass side above the fuel tank just right of the canister assy there is a series of junction plugs they connect the out side stuff to the inside harness ie fuel tank,abs,canister ect. I find the fuel tank connector its on the top of the 3 connectors I unplug it and I nice bit of water comes out of it so now I'm thinking here we go. so I get it out look at both sides of course corrosion all over get the terminal brush out and start cleaning all the terminals I get them all clean plug the connector back in and check the meter now shows 5v perfect so at this time I go back under pull the connector apart and apply contact grease to is so I can prevent any further issues hope this helps someone else down the road. I cleared the codes everything works now no cel car is out of limp

aradmahogany

Stop offroading through large puddles! In all seriousness, glad you got it fixed

Conax

Good job! I had a problem that was similar and cleaning the plugs up under there fixed it right up.
(It was an intermittent ESC/Trac warning) A little contact cleaner and done.

Oldblue

I just swapped my fuel pump last month, glad it was 60 out then and not the 10 degrees F it is today, I checked all those connections by the fuel tank and the EVAP canister, they were thankfully all dry, I did apply some dielectric grease and ensured they were packed and connected secure, and dry.
Thank you for confirming this could have been a trouble spot!




Baby it’s cold outside!!