Help, Trouble Code P1600 With Lots Of Greyish White Smoke, Unburnt Fuel
11-27-08, 11:00 AM
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Help, Trouble Code P1600 With Lots Of Greyish White Smoke, Unburnt Fuel
HELP, My baby is sick!!!!!!!!!!!!!!!!.
I was driving late at night and my 96 LS400 developed a check engine light, there was no power loss or any misfiring so i kept on driving as my home was near. I stopped at a signal and the check engine light started flickering with TRAC doing the same. Engine was revving like crazy with light white smoke which was light at first then it started to get pretty thick, I had to switch the car off and put my Hazard on. It was though I had blown off a gasket, piston or something.
I was close to home so I decided to take a chance and restart my car just to see what happens, this time it started with the check engine light on but no smoke. Eventually I limped home without any majour exhaust issues.
Next day i restarted the car, initially there was no smoke but then it started again, stuttering engine, raw fuel smell and lots of smoke. I looked at the the Trouble code, it was P1600, which pointed to an issue with ECU battery malfuntion,
looked up the Forum here http://us.lexusownersclub.com/forums...ode=linearplus
this gives a good idea to troubleshoot this code. it says to perfom the following test to see if the ECU is bad
a. remove instrument undercover and measure voltage between terminal battery of ECM and body ground.
I tested the connector as advised, there seems to be no voltage at all at the connector. i further went on to check the fuse and tried detecting a voltage and could not find any voltage coming there too!!!!. IS THE HARNESS FRIED?. how can i further test this?.
I wanted to point out that before this issue happened I had changed my motor mounts. i remember the mechanic had a hell of a time removing one of the mount and he had to jack the engine up like crazy. would that have caused damage to the harness?. Did anybody have this experience?
I opened the ECU too.. found all capacitors leaking, blank gunk on the circuit board. I want to further go ahead and clean this using electrical cleaner. let me know if it is OK? should i go ahead and replace the capacitors too?
After seen the gunk, How do I know the ECU is fine? is there a test I can perform to Verify 100%?. My OBCD reader connects to the ECU to get the P1600 code so can i presume ECU is good?. can i supply Voltage directly to the ECU, By attaching a wire directly to the ECU?. In that case what should the voltage be?. 12V?
Gurus Kindly respond. Thanks.
Thanks for the Help Guys -- Tan
I was driving late at night and my 96 LS400 developed a check engine light, there was no power loss or any misfiring so i kept on driving as my home was near. I stopped at a signal and the check engine light started flickering with TRAC doing the same. Engine was revving like crazy with light white smoke which was light at first then it started to get pretty thick, I had to switch the car off and put my Hazard on. It was though I had blown off a gasket, piston or something.
I was close to home so I decided to take a chance and restart my car just to see what happens, this time it started with the check engine light on but no smoke. Eventually I limped home without any majour exhaust issues.
Next day i restarted the car, initially there was no smoke but then it started again, stuttering engine, raw fuel smell and lots of smoke. I looked at the the Trouble code, it was P1600, which pointed to an issue with ECU battery malfuntion,
looked up the Forum here http://us.lexusownersclub.com/forums...ode=linearplus
this gives a good idea to troubleshoot this code. it says to perfom the following test to see if the ECU is bad
a. remove instrument undercover and measure voltage between terminal battery of ECM and body ground.
I tested the connector as advised, there seems to be no voltage at all at the connector. i further went on to check the fuse and tried detecting a voltage and could not find any voltage coming there too!!!!. IS THE HARNESS FRIED?. how can i further test this?.
I wanted to point out that before this issue happened I had changed my motor mounts. i remember the mechanic had a hell of a time removing one of the mount and he had to jack the engine up like crazy. would that have caused damage to the harness?. Did anybody have this experience?
I opened the ECU too.. found all capacitors leaking, blank gunk on the circuit board. I want to further go ahead and clean this using electrical cleaner. let me know if it is OK? should i go ahead and replace the capacitors too?
After seen the gunk, How do I know the ECU is fine? is there a test I can perform to Verify 100%?. My OBCD reader connects to the ECU to get the P1600 code so can i presume ECU is good?. can i supply Voltage directly to the ECU, By attaching a wire directly to the ECU?. In that case what should the voltage be?. 12V?
Gurus Kindly respond. Thanks.
Thanks for the Help Guys -- Tan
11-29-08, 08:43 PM
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I had a suspicion that the ECU is bad but today its confirmed. I had a doubt that the harness can be the issue as a result of the Engine Mount's change. but I
finally found out that I was testing the voltage to the ECU incorrectly at the wrong connector.
http://us.lexusownersclub.com/forums......ost&id=7266
the battery terminal "BATT" has to be accessed from behind the connector. It is the first slot as shown in figure.
I was incorrectly testing from the opposite side, being a mirror image the connector slot was wrong and I was getting no voltage at all. I got 12V proper at the
right BATT terminal, just to be 100% sure I was testing the right connector I went ahead and disconnected the EFI no 1 Fuse, This broke the connection,
so it is confirmed that there is an issue with the ECM and not the Harness.
I have found a replacement ECU for about 100$ from a Salvageyard and gone ahead and ordered it. My only concern is that my Key will not work. also my car
is equipped with traction control, will it support that Logic?. I will be lucky if it will be 100% fit. but otherwise what option do I have? can the original
programming transfer from my old ecu to the new one? I also spoke with people who fix ECU's, he said possible for $250
will this be a good approach? any body done this?, any issues later? THANKS.
finally found out that I was testing the voltage to the ECU incorrectly at the wrong connector.
http://us.lexusownersclub.com/forums......ost&id=7266
the battery terminal "BATT" has to be accessed from behind the connector. It is the first slot as shown in figure.
I was incorrectly testing from the opposite side, being a mirror image the connector slot was wrong and I was getting no voltage at all. I got 12V proper at the
right BATT terminal, just to be 100% sure I was testing the right connector I went ahead and disconnected the EFI no 1 Fuse, This broke the connection,
so it is confirmed that there is an issue with the ECM and not the Harness.
I have found a replacement ECU for about 100$ from a Salvageyard and gone ahead and ordered it. My only concern is that my Key will not work. also my car
is equipped with traction control, will it support that Logic?. I will be lucky if it will be 100% fit. but otherwise what option do I have? can the original
programming transfer from my old ecu to the new one? I also spoke with people who fix ECU's, he said possible for $250
will this be a good approach? any body done this?, any issues later? THANKS.
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