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Replaced the ecu. No security/key relearn required, the 30 min one with the ignition key. It was easy enough. There's a CEL that i have to check, must be asking for crankshaft relearn. What's the best way to clean the connectors on the ecu? I have electronics spray cleaner.
That didn't stop the battery from dying repeatedly after charging it and being told the battery was still "good".
When the cold set in here in December, it's reserve capacity went down to nothing. Probably from the rad. cool fan running continuously from when my hhr started to about 7 minutes after it's turned off. Replaced the battery.
The cool fan still runs continuously from startup to about 7 min after shutoff. I pull the relay, it stops, and plug it back in and it runs. I've swapped out the relay with a similar one for the rear defogger and the fan continues to run, so hopefully that rules out a sticky relay. It's seems that something beside the ecm is telling it to. So I pulled the relay and have kept it out while also monitoring the DIC coolant temp. It's cold enough here right now it's keeping the temp at 199 while sitting idling. I have a gallon of dexcool, the recommended acdelco tstat, and an acdelco ect sensor. Should've done the dexcool first probably. Should I continue this conversation about the cooling fan in the thread that left off where i seem to be at: https://www.chevyhhr.net/forums/prob...e2/#post919758
Let me pickup where the previous OP left off, my ride has the same symptoms. Gremlins
On my 08 LT 2.4L 115K HHR, The cool fan runs continuously from startup to about 7 min (possibly exactly 7 min) after shutoff. I pull the relay, it stops, and plug it back in and it runs. I've swapped out the relay with a similar one for the rear defogger and the fan picks up where it left off before the relay was pulled. Does that rule out a sticky relay?. It's seems that something beside the ecm is telling it to. So I pulled the relay and have kept it out while also monitoring the DIC coolant temp. It's cold enough here right now (avg.5-10°F) it's keeping the temp at 199 while sitting idling. I have a few gallons worth of dexcool (1 50/50 & 1 full concentration), the recommended acdelco tstat 131-158?, and an acdelco ect sensor. Should've done the dexcool first probably. It could use all this stuff anyway even if it's not directly responsible for this gremlin. I'll update after i make more progress...
You leave the most important bit of data out: what is the digital engine temp when this happens? Than is supposed to stay on for 3 minutes if the temp is above 284F/140C.
199F idling is a bit high, not an alarm, just a bit high should be about 190F.
It happens in winter, below freezing, with a cold engine.
Ya it happens regardless of engines temp. I didn't realize earlier that the fan starts up as soon as the car is started too full blast (full blast? Are there different fan speeds?).
I was expecting p0315 after replacing ecm/ecu asking to have crankshaft position relearned. But got p0300.
I was expecting P0315 after replacing the ecu/ecm...
I removed the relay for the (rad) cool fan because it runs continuously from startup to about 7 min after shutting off car, regardless of temp and run time and conditions.
Why not keep it all in one thread? P0480 is the relay CONTROL circuit; meaning the wire between the relay and the ECM is grounded somewhere, since you already replaced the ECM.
The P0300 is most likely because the crankshaft data is incorrect, a P0315 only means it is an empty memory slot a used ECM will have the donor's data unless it gets cleared.
Any chance a previous owner was smarter than the GM engineers and added a fan switch or similar.
The "book" claims that the fan is 2 speed, but it describes a circuit with 2 relays, In the paragraph before that is describes a 1 relay one speed fan. Since we only have 1 relay, I assume it is 1 speed.
Have you verified that the AC compressor is NOT running?
01-08-2022, 12:43 PM
