Hello, I've been having a real irritating problem with my 2001 sentra 1.8 (qg18de) automatic series 1(cable throttle). After about 40mins of driving the car will start slipping between gears, mostly 1st and 2nd gear. Transmission was replaced last summer with 20 000 succesful km done so far. Transmission fluid is at the right height and is still red and not burnt. When i leave in the morning or night the car is fine for about 40mins. The check o/d light will flash exactly 16 times very fast all equal distances, upon starting it after many hours of sitting. I cant find anything talking about 16 flashes. There is no engine/trans codes appearing i checked with my code reader. There is a code telling me the car is running rich but thats been for 3 years now. I am completely stumped, and i really need this car since im still paying it off.

Hi.

If the O/D light was on, then a transmission problem has occurred.

Theproblem may had been occasional. There are many different conditionsthan a simple contact that can cause this (from a slipping transmissionto a bad ground). The O/D module light flashes when an automatic transmission fault has been detected by the ECU.If the problem happens again there may be codes stored in the ECU andprobably in TCM even if check engine light does not come on.

Youcan first try disconnecting battery ground cable for five minutes. Thiswill reset the ECU. If possible do a code scanning before doing thisoperation. Disconnecting the battery you will also reset the errorcodes stored in the car module. Ensure that you have c anti theft code if needed.

The first step in troubleshooting is reading fault codes.

Ifthe problem is an auto transmission not shifting correctly, then commonfaults are TPS sensor, TCM (transmission control module), Transmissionshif solenoid and more.

If the car is drivable, then a code scanning can be performed for free at the nearest Autozone.
Whenproblem is transmission you often get a P0700 error, that would meanthat more codes are stored in a different module (TCM). The TCM can bescanned at the dealer or at an autorized garage.
Other codes (like P0500, vehicle speed sensor), will point directly at the faulty part that is causing trnsmission malfunction.

As mentioned, the TCM is the computer modulecontrolling the transaxle, see: I get code p0700 after an OBDII scan.
Thereare many possible reasons for automatic transmissionmalfunctions. Mostcommon transmission malfunctions are discussed here:My car does not shift..

If you want to do the code scanning by yourself, you will need to use an OBDII tool like this one:Autel MaxiScan MS409 OBD-II/EOBD Scanner

If there are no OBDII codes, then the O/D codes can be scanned with a Com tool available at certified garage.

Note: The 16 times flashing it is not a code. The codes are short and long.


Regards.

Ginko.