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Discussion Starter #1
my car quit on the road no code but reduced engine power and disabling engine came up. took it to the dealer and they say bad ecu. 700.00 to replace ? on programming. took it home and today wouldn't you know it won't start. scan Gage now says p0601 bad ecu. so now what options do i have? can i get an ecu from the junk yard and plug it in and go or do i have to spring for the 100.00 repair at the dealer? or can i get a junk yard ecu and jut take it to the dealer with my vin and have them program it on the bench? or can i send mine or another one in to a repair shop and have it repaired or re-programed and just plug it back in and go? thanks
 

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Is this for a Cobalt? What year? What options?
 

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Discussion Starter #3
cobalt 06 2.2 auto lt power everything window mirrors steering wheel controls anti theft cruise a/c and what ever else come is that package vin is 1g1a155f867722153 thanks
 

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Disconnect battery, remove both connectors of the "PCM" remove it from it's slot inspect and clean connectors. Re-install and insert connectors several times to help clean contacts from corrosion. Wait 15 minutes. Re-connect battery and try starting your car.
 

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Discussion Starter #5
Disconnect battery, remove both connectors of the "PCM" remove it from it's slot inspect and clean connectors. Re-install and insert connectors several times to help clean contacts from corrosion. Wait 15 minutes. Re-connect battery and try starting your car.
did that still won't start. i did manage to get one code before the scanner failed to reconnect that was p0601. i found out was a failed ecu internal problem. do you happen to know if i can get a junkyard ecu and plug it in or if not can i just bring in a ecu and get it bench programed or just buy one from gm have them program it with my vin number and plug it in? thanks
 

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Well P0601 is a PCM ram checksum error so more than likely the dealer was right. Since the PCM is a non-serviceable part you might need to get an other one. Any garage with a Tech2 can erase and reprogram a PCM if he knows what he's doing and pretty sure the dealer will reprogram a used one for you, they just can't warranty the work.
 

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Discussion Starter #7
i figured that would be the case but do you know if they need the car in the garage or can it ake the ecu to them for programming?
 

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Yes, the "PCM" has to be in the car for it to be programmed and matched to the "BCM","TDM", "TCM" and "ABS" module. Your new PCM will have to do a re-learn at some point and I think it is better to let somebody with experience handle it. They can erase and program your VIN, but this has to be done through the OBDII connector so does the re-learn process. You can do a re-learn without the TechII but you will eventually need the TechII to clear all the codes encountered during the process. Some of which might leave your engine in limp mode until viewed and cleared.

I know How you feel I hate going to the dealer also but sometimes it's the only option. I even bought a TechII for myself to try and avoid the dealer lol....
 

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Discussion Starter #9
so if i was to get one of these tech ll scanners i could put in a different ecu and then make it read all the other computers in my car? does the scanners come with all the programming to do this? and will it have the program to make the car run or will i have to download this program? if so where can i get it. also are these scanners complete or cables and software i then you a laptop with? thanks
 

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TechII cost 3500$, 800$for TCIS log in license and password for one year only. Better to go to dealer or friendly mechanic that has one and knows what to do.
 

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Discussion Starter #11
thanks for the answer. your correct better to just spend the money and get them to do it. but it never hurts to ask. because i could have wound up spending money for a procedure i can do myself. thanks bob p.
 

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I know what you mean, because I'm the same way, bringing it to the stealer is my last resort. Been screwed from behind too many times.
 

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Discussion Starter #13
so does anyone happen to know if there is a place i can send the ecu to to get it repaired? seems that will be way cheaper than a new one and then have to get it all reprogrammed? thanks bp.
 

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corvairbob,

I see that you're looking to head into a dealership (possibly) for the programming procedures; keep us updated on your progress there! If there is anything you wanted for me to check into be sure to let me know. For the record, I checked the VIN you had provided earlier in the thread and there aren't any open recalls on your vehicle at this time.

Sarah, GM Customer Service
 

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Discussion Starter #15
well today i got the ecu changed out and 700.00 bucks later i drove it home. got home and i got this code that will not reset. p0315
Possible causes
- Crankshaft Position (CKP) sensor harness is open or shorted
- Crankshaft Position (CKP) sensor circuit poor electrical connection
- Faulty Crankshaft Position (CKP)
- Damaged crankshaft pulse wheel teeth.
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Engine fails to start
- Engine runs rough

did not have this problem before the ecu failed unless that cause the failure? bp.
 

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Discussion Starter #16
well i got the ecu replaced Saturday. 700-00 later drove it home. on the way home the engine lite came on. code p0315. my scanner tells me this is the crank position sensor not learned. it is running so it either takes time or that sensor has a problem. i think it is under the engine by the pulleys? so i will replace that sensor this week. could that have caused the ecu to fail? one more question my mileage has been dropping some the last few months it use to get 32 highway miles now it is at 30. it has 97k on it so i;m thinking the o2 sensor may need replacing. which one usually causes this the front sensor or rear sensor. on my s10 it was the front. my understanding is the front o2 sensor is used for the mileage and the rear is used for checking the cat. thanks bp.
 

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They must have forgotten to do the crankshaft variation learn procedure. Because that code doesn't mean your sensor doesn't work it just means the recorded parameters aren't right or not programmed.

DTC P0315
Circuit Description
The Crankshaft Position (CKP) system variation learn feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the CKP sensor. The calculated error allows the powertrain control module (PCM) to accurately compensate for reference period variations. This enhances the ability of the PCM to detect misfire events over a wider range of engine speed and load. The PCM stores the CKP system variation values after a learn procedure has been performed. If the actual crankshaft position variation is not within the CKP system variation compensating values stored in the PCM, DTC P0300 may set. If the PCM detects that the CKP system variation values are not stored in the PCM memory, DTC P0315 sets.
If you paid 700$ to get it programmed they should do a complete re-learn not just a theft deterrent re-learn.

---------- Post added at 11:14 AM ---------- Previous post was at 11:10 AM ----------

Crankshaft Position System Variation Learn
Important: The crankshaft position (CKP) system variation learn procedure is required when the following service procedures have been performed, regardless of whether DTC P0315 is set:

• Engine replacement

• Engine control module (ECM) replacement

• Crankshaft damper replacement

• Crankshaft replacement

• CKP sensor replacement

• Any engine repairs which disturb the crankshaft to CKP sensor relationship


Important: The scan tool monitors certain component signals to determine if all the conditions are met to continue with the CKP system variation learn procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components:

• CKP sensor activity--If there is a CKP sensor condition, refer to the applicable DTC that set.

• Camshaft position (CMP) signal activity--If there is a CMP signal condition, refer to the applicable DTC that set.

• Engine coolant temperature (ECT)--If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature. Install a scan tool.
Monitor the ECM for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to Diagnostic Trouble Code (DTC) List - Vehicle for the applicable DTC that set.
With a scan tool, select the CKP system variation learn procedure and perform the following:
3.1. Observe the fuel cut-off for the applicable engine.

3.2. Block the drive wheels.

3.3. Set the parking brake.

3.4. Place the vehicle's transmission in Park or Neutral.

3.5. Turn the air conditioning (A/C) OFF.

3.6. Cycle the ignition from OFF to ON.

3.7. Apply and hold the brake pedal for the duration of the procedure.

3.8. Start and idle the engine.

Important: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine responds to throttle position after the learn procedure is complete.

3.10. Release the throttle when fuel cut-off occurs.

The scan tool displays Learn Status: Learned this Ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, refer to DTC P0315 . If any other DTCs set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for the applicable DTC that set.
Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.
 

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Discussion Starter #18
thanks it will go back tomorrow and they can fix it on the spot. sounds like the tech can do it in the parking lot? the 700$ was to replace the ecm. i chose to have a new unit installed because we are keeping the car and traded in the saturn for a hyundai sonata hybrid. bp.
 

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So are you saying they installed it and never did the re-learn procedure?

Hyundai Sonata hybrid; my friend bought one of those and he loves it. I would buy one except I know the dealership owner. He's a total *$$.
 

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Discussion Starter #20
tell me if i can do any of this at home using a scan gage tool and not a dealer gage? just in case i ever had to do any of the parts replacements listed above? or will it still need to go back to the dealer for this procedure? thanks
 
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