# Transmission slipping



## 21modelt (Jul 6, 2019)

I bought a 2005 Altima for my daughter and now I'm having a few little problems. The other day she came home and the car seemed to be slipping in the transmission. It would just rev up and hardly move. The service engine, slip and TCS light would come on. When I had the codes scanned it pulled a code of P1800. But would that code have anything to do with transmission? When I drve the car later just the engine light was on and it drove fine. The transmission fluid looks and smells new. Any ideas? Thank you


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## rogoman (Dec 16, 2004)

The P1800 fault code is set when the VIAS control solenoid valve is malfunctioning. Normally the VIAS provides the intake manifold vacuum signal for power valve control; when the engine is running at low or medium speed, the power valve is fully closed. Under this condition, the effective suction port length is equivalent to the total length of the intake manifold collector's suction port including the intake valve. This long suction port provides increased air intake which results in improved suction efficiency and higher torque generation. The VIAS circuit problem has nothing to do with the transmission problem.

The TCS (transmission control system) may be locking up the brakes causing the car not to move. If a wheel speed sensor is not functioning correctly, then the TCS will think that the vehicle is slipping on the road and will apply the brakes to that wheel. Check the wheel speed sensors for any dirt or oil on them. Check the wires to them and see if the wires are connected and secure. Also, look under the vehicle for any damaged areas or anything out of the ordinary. There may be additional fault codes produced by the TCS that your scanner is not capable of picking up. First, there's a bit of a difference between an OBD (Code) reader and a scanner. Readers only report error codes (and sometimes a limited amount of. ... while scanners provide a broader scope of live data.


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## 21modelt (Jul 6, 2019)

Thank you for the quick response. Is the car still driveable with a VIAS control solenoid failing? I also had the parts store scan the car and they came up only with a cam sensor code ( I dont remember the code ) is it possible that a cam sensor can trigger a TCS or Slip light to come on?


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## rogoman (Dec 16, 2004)

A failure of the VIAS control solenoid will NOT cause the ECU to enter into fail-safe mode; so yes, the car is still driveable. A camshaft sensor problem could possibly affect the TCS depending what the problem actually is. We need to know what the actual code is to further help you. Beware of this; a failing camshaft sensor can possibly cause your engine not to start or the engine can suddenly shut off while you're driving on the road; you need to get that fixed ASAP.


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## 21modelt (Jul 6, 2019)

P0340 was the code that the auto parts store gave me for s faulty cam sensor bank one. I did replace it and cleared codes so we'll see if this fixes this random problem.


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## smj999smj (Jan 1, 2006)

When the ECM detects an engine management issue, such as a bad cam sensor, it will disable the traction control system, causing the TCS system warning light to come on. Hopefully, you got a decent brand like Hitachi or SMP/Intermotor because aftermarket sensors can be a little "iffy." I usually get the Nissan "sensor kit." P/N B3731-6N21A. It was the kit they used in the recall and has both the cam and crank position sensors for about $50. As far as the VIAS system, one thing you have to watch out for on these engines is sometimes the power valve screws will fall out into the engine. Not all of them received enough thread-locker at the factory. Unfortunately, the only way to check them is to remove the intake.


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## 21modelt (Jul 6, 2019)

UPDATE. Just got back from a weekend driving trip with the Altima and it ran flawlessly. No problems whatsoever


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