ALLANC

Need some guidance please. Neighbour lady has a 96 LS400. Issue started with a P0115 code. Turned to a P3006 and list the coolant code. I replaced #6 injector and it sat and idled for 20 mins as smooth as can be. Revved it a few times. She took it to get gas and put some injector cleaner in it. Ran fine going there but on the way back, started missing and smoking. Put the code reader on and got a P3002 and 3008, no 3006. New plugs and leads got installed this past weekend. Throwing the P0115 now and can't get any other codes. I didn't drive it far due to the volumes of smoke. Any suggestions boys and girls?
Thanks in advance.

aptoslexus

P0115:  Open or short in engine coolant temp. sensor circuit
 Engine coolant temp. sensor
 ECM

I think that's where I would be looking.

ALLANC

I am just trying to understand the misfire and smoke. The smoke is definitely excess gas but trying to understand that coming from the coolant sensor.

aptoslexus

Courtesy of http://www.obd-codes.com/p0115

symptoms of a P0115 DTC code may include: MIL (Malfunction Indicator Lamp) illumination will always occur Vehicle may be hard to start May blow a lot of black smoke and run extremely rich Engine may want to die or backfire in tailpipe Engine may run lean and increased Nox emissions may be apparent (Requires gas analyzer) Cooling fans may run all the time when they shouldn't be, or not at all when they should be Causes Usually the cause can be traced to a bad ECT sensor, however that doesn't preclude the following: Wiring or connector damaged at sensor Open or short in reference or signal circuit Open or short in signal circuit Bad PCM

ALLANC

I appreciate your help. I will go ahead and buy a sensor, the car has 200k miles on it so not going to hurt. I can check for a short once I get it all apart.

dicer

Coolant temp sensor is a key sensor. When cold it will tell the ecu to enrich the fuel just like the old choke days. If its not working correctly and after the engine warms up it will then over richen the mixture and cause black smoke and misfiring.

UNCNOR

iTrader: (1)

What color is the smoke?

Yamae

Those 4 codes P0115, P3002, P3006 and P3008 are usually not related. But those 4 are sometimes caused by the poor regulation of the low voltage DC power supply circuit in the ECU.
Don't you have any AT shifting problem?

ALLANC

I am not aware of any shifting issues, mind you, I drove the car for the first time yesterday. Only showing the P0115 now. Tried to kick some more codes by taking it for a drive around the block but had to turn back before I got arrested for polluting the air with all the smoke.

RA40

iTrader: (6)

+1. Along those lines check the coolant and pull the engine oil dipstick. The Idle Air Control Valve is the next suspicious item but those don't puke out white smoke like a blown head gasket.

ALLANC

Coolant and oil look good. I will change the coolant sensor first and then follow on from the result.

Thanks for you help.

ALLANC

The smoke is white.

UNCNOR

iTrader: (1)

Water in the gas?

ALLANC

I am very suspicious of the gas and additive that she put in the tank. It was smooth until she filled the tank.

UNCNOR

iTrader: (1)

Has the problem been solved?Please let us know.