Engine reduced power

RANYRIZK

MEMBER
2003 CADILLAC CTS
129,000 MILES

My car made some discontinuity like an impact at the brake when the speed is reduced.
a little bit later it give the warning "engine reduced power" and the throttle pedal become useless.
The scanner gave codes

P1779
P1795

and sometimes P0700

once the DTC are cleared the car works normally for a random time and the fault come back.
I changed three times the throttle body but the defect come back some times in six months and last time in less than 3 weeks.

could you help me please. And does the engine oil vapor, due to a small leak above the catalytic converter, causes the throttle body defection?
regards

5 Replies

HMAC300

MECHANIC
48,601 POSTS

No the vapor shouldn't the 0700 is a transmission control module problem and the p1795 may be the real problem. That may be why you have tried replacing the throttle bodies and still not having success. This because you may need a new trans control module and they are vin specific so you can't get another out of another car.

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Tuesday, September 3rd, 2013 AT 12:23 PM

RANYRIZK

MEMBER
39 POSTS

The connector of the hatness entering to the gearbox was broken (see picture).
I guess it is the cause of the problem.
Thank you all and sorry for disturbing

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Friday, September 27th, 2013 AT 12:48 AM

HMAC300

MECHANIC
48,601 POSTS

This is a great example of a code reader telling you one thing but it is an entirely different problem altogether. That is why it's hard to diagnose by just replacing a part or even coming on here as yours was an entirely different problem but cause the code that you got as well as having to replace other parts. We are not infallible but try as we can, can't always solve the problem glad you go it fixed and found the real problem. Thanks for using 2car pros

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Friday, September 27th, 2013 AT 7:34 AM

DIARRHEA JOHNSON

MEMBER
1 POST

What harness was that and where? I have same issue. Intermittently shifting works. But it gets stuck in 3rd or 4th most all time and no PRNDL indication on shifter then once in a blue moon it'll work and I can drive with all the gears and p0700 always on. Usually no other codes pop which is usually unheard of. This has been months by the way. Now check has a p1795 p1799 and always the p0700. Key wouldn't come out of ignition due to lack of PRNDL not knowing what gear it was in and I found many saying replace ECM which I had done and same issue now I have TCM on order and am going to search this harness if you tell me where to look. I assume going into transmission or coming off connector to TCM. Any help would be superfragilistic. Thank you

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Saturday, January 4th, 2020 AT 8:45 AM

KEN L

MASTER CERTIFIED MECHANIC
42,878 POSTS

This is the connector that attaches to the transmission. You will need a new wiring harness unless you can fix the connector here is a diagram to help. Check out the diagrams (Below). Please let us know what happens.

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