2006 Chevrolet Cobalt Cobalt won’t start after ecu installation
Cobalt won’t start after ecu installation
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My 2006 cobalt LT 2.2L started running rough a couple of weeks ago. So I cleaned the throttle body - didn’t help. At this point I got 2 engine codes - P0106 map sensor and P0300 random misfire. I put in a new MAP sensor (standard parts brand) - didn’t help and I put the original back in.
At this point I took off the ecm - it plugs into the coil bank. I cleaned the terminals and plugged it back in. Now the car would not start. When I turn the key to on I do not hear the fuel pump run. When I try to start the car I hear the starter motor turn the engine but it does not fire up.
I put in a new ecm (standard parts) - didn’t do anything. Put the original ecm back in. Checked the plugs and they look good. Checked the ecm contacts and they look good. The fuses look good.
I’d like to first get back to where the car was running rough. The no start problem was the result of my removing and reinstalling the ecm.
Would appreciate any suggestions.
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I had to reregister because of some glitch.
But in answer to two questions:
I did check the fuses
I don’t think the emu can be programmed. This component is sometimes called the ignition control module. It sits on top of the engine in the coil pack unit.
It is quite possible you have damaged the pin terminals inside the wiring connector to Icm.
You can purchase a kit that includes the icm and coil pack for approximately $100.00.
Good luck!
Unless you attempted repair elsewhere - the icm wiring is the only logical suspect..
That’s the only thing that could have changed as I see it.
Again - good luck.
I’ll keep this short - pump runs for 2 seconds when key it turned on - then it turns back off.
Quite possible the icm circuit turns pump back on once engine rotation is detected.
You’ll need a wiring schematic and diagnostic flow chart to run down the related circuits.
IF you do not hear the fuel pump at any time - there is a fuse for the pump - TEST IT - don’t assume anything.
Try to keep in mind there was no fuel pump problem prior to your attempted repair!
Connector voltage test
As a follow up, I tested the voltages at the input to the ignition control module with the ignition key in the on position. Looking at the connector with the release mechanism at the top, there are 5 positions along the top row and 4 along the bottom. Numbering from left to right 1) to 5) and 1) to 4)
Top row: 1) black wire 0 volts, 4)white wire 4.7 v, 5)red wire 11.3 v.
Bottom row: 1) brown with white stripe wire .08 v, 2) orange wire 4.7v.
When I clipped on a battery pack the voltages rose from 4.7 to 5v and from 11.3 to 12v respectively. The car battery is no doubt run down.
There isn’t much else we can offer here online - this is simply something that requires the vehicle to be present for *hands-on* testing / evaluation.
As noted I did try a new icm. I think the fact that the fuel pump is not firing up has some significance.
Unless you attempted repair elsewhere - the icm wiring is the only logical suspect.. That’s the only thing that could have changed as I see it. Again - good luck.
Could that account for the fuel pump?
I’ll keep this short - pump runs for 2 seconds when key it turned on - then it turns back off. Quite possible the icm circuit turns pump back on once engine rotation is detected. You’ll need a wiring schematic and diagnostic flow chart to run down the related circuits. IF you do not hear the fuel pump at any time - there is a fuse for the pump - TEST IT - don’t assume anything. Try to keep in mind there was no fuel pump problem prior to your attempted repair!
Don’t hear fuel pump at any time. You are saying the icm controls the fuel pump?
Connector voltage test As a follow up, I tested the voltages at the input to the ignition control module with the ignition key in the on position. Looking at the connector with the release mechanism at the top, there are 5 positions along the top row and 4 along the bottom. Numbering from left to right 1) to 5) and 1) to 4) Top row: 1) black wire 0 volts, 4)white wire 4.7 v, 5)red wire 11.3 v. Bottom row: 1) brown with white stripe wire .08 v, 2) orange wire 4.7v. When I clipped on a battery pack the voltages rose from 4.7 to 5v and from 11.3 to 12v respectively. The car battery is no doubt run down.