Ok so for the last week check engine has been on, I looked everything over and nothing was low as far as fluids. Nothing seemed lose or broken. Car was running fine no real problems that I could see or feel. Coming home from work in the snow, check engine light started flashing and the engine started running rough and vibrating. I got home and went and had the codes checked. 1st code was P0404 which is for the EGR valve, which is what was probably having the check engine light on in the first place. the 2nd code was P0302 miss fire #2 cylinder. Any ideas as to what could be causing this. I dried everything off under the hood as it did get snow up under there. I drive 45 miles one way to work. Motor still has vibrating and check engine flashing. My only vehicle so I need to solve this quick! Thanks for any info guys and gals.




2002 Monte SS 3.8 engine

 

P0203 - Cylinder 3 Injector Circuit Malfunction



Cylinder 3 Injector Circuit Malfunction
What does that mean?

P0203 means that the PCM detected a fault in the injector or the wiring to the injector. It monitors the injector and when the injector is activated, the PCM expects to see the voltage pulled "low" or close to zero.

When the injector is switched off, the PCM expects to see a voltage that is close to battery voltage or "high". If it doesn't see the expected voltage the PCM will set this code. The PCM also monitors resitance in the circuit. If the resistance is excessively low or high it will set this code.
Potential Symptoms

The symptoms for this code will likely be a misfire and a rough running engine. Poor acceleration. The MIL will also be illuminated.
Causes


The causes of a P0203 engine light code could be any of the following:

• Bad injector. This is usually the cause of this code but doesn't rule out the possibility of one of the other causes
• Open in the wiring to the injector
• Short in the wiring to the injector
• Bad PCM

Possible Solutions

1. First, using a DVOM check the resistance of the injector. If it isn't within specs, then replace the injector.
2. Check for voltage at the fuel injector connector. It should have 10 volts or more.
3. Visually check the connector for damage or broken wires.
4. Visually check the injector for damage.
5. If you have access to an injector tester, activate the injector and see if it operates. If the injector operates, then you likely have either an open in the wiring, or a blocked injector. If you do not have access to a tester, swap the injector with another one and see if the code changes. If the code changes, then change the injector.
6. At the PCM, remove the driver wire from the PCM connector and Ground the wire. (Make sure you have the correct wire. If you're not sure, do not attempt) The injector should activate
7. Replace the injector

 

Thanks Stumpi but I am getting a P0302 code would that be the same for it as your code #P0203?

 

Whoops my bad...
Gimmie a minute...lol
Lets see what I can find.

 

Symptoms

Symptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

Causes

A code P0302 may mean that one or more of the following has happened:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer

Possible Solutions

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

 

Good post with excellent diagnostics stumpmi!

I also suggest not driving the car like this as it will even cause more damage!

 

Thanks Stumpi, and Turbo Monte, I got it home last night and its going to the garage first thing tomorrow morning. Already called my buddy from the garage and he is expecting me first thing, as he knows how much I need this car running right.

 

Your Quite welcome DJ!

Thanks John..
I try...
That's why were here...
Were here to help!

 

FYI - Moved this to the "Monte Carlo Repair Help" section.

 

Thanks Jason...
My bad I didn't think to check that it was under the correct topic...lol
I guess I was preoccupied with giving him a correct/helpful answer first...lol