My Grandson stopped for gas and his 2004 Limited would not start. He said after several tries it had a loud bang and there was smoke. He tried hooking up his code reader and it would not communicate. Any thoughts? I assume the bang and smoke was a backfire. The OBD2 issue I have no idea. He lives a distance from me so it is difficult to trouble shoot.

 

Way too little information to troubleshoot remotely

If the ODBII does not communicate let's start with the battery and RCM. I hope the computer did not die.

 

First, you have been around here long enough to know that "won't start" is meaningless. Did it engage the starter or not?
A failed RCM (if it won't engage the starter) or Crank sensor (if it engages the starter but won't start) are common "no start" causes.
If the code reader can't talk to the ECU, then I'd suspect that the RCM not powering up the ECU.

But none of this explains a 'loud bang and smoke'.

 

Thank you for the ideas. Yes, the starter engages thus the backfire. I also suspect the CPS, RCM or MAF. The new wrinkle was the backfire/smoke and lack of communication.

 

Hi Zeracer,
Is the issue repeatable, e.g. does it still crank and backfire, or was that a one-shot event? You might have two issues, like the CPS failed followed by the RCM
-Jerry

 

Plugged catalytic converter

 

I am still not sure what you are describing. No communications with the ECU implies it is not powered up, but in that case, the starter won't engage.
But a backfire, if that is what he really heard, means the ECU is powered up because the plugs fired.

There just is not enough here to go on. As someone else asked, did the car finally start and run? Has it done it again or is it doing other weird stuff?

 

I'll get more info from my Grandson today. Thanks to all for the input.

 

Wouldn’t it be a lot easier to hear from him about what’s going on rather than going through a middleman?

 

I have been here since 2006. I have two Crossfires and gave my two Grandsons each one. I have just never heard of an issue with a backfire and communication loss. You are correct I should have waited for more info before reaching out.

 

Okay, he finally responded after getting the following messages on the DRB2. It cranks and tries to fire. There are four messages. They are "linking error", "Verify that the ignition is on and check that the scan tools drb connector is securely connected", Verify that the vehicle is DRB2 compliant" and " Turn the ignition off, wait 10 seconds and turn the ignition back on". I will try to drive out there and look at it soon.

Thanks for any thoughts.