Won't go to overdrive (4th gear)
iceman2
03-02-2010, 02:52 PM
1997 PT, 165k miles, 3.4L; will not shift to highest gear. Stays in 3d, and at 70 miles per hour, RPMs are close to 3k, costing me gas mileage. The transmission fluid was low however I added and it is now at the right level. No other indicators or malfunctions relating to transmission; I do have 2 trouble codes: P1655 and P0121, but these are emission issues. Thanks for any help or advice.
LMP
03-02-2010, 06:09 PM
P0121 this is it: throttle position sensor. A classic. THis trouble inhibits 4th, TCC and cruise control. Change TPS.
iceman2
03-03-2010, 08:35 AM
Thanks, I'll report back.
iceman2
03-04-2010, 09:17 AM
Thanks, I'll report back.
How difficult is it to replace the TPS? I just ordered one from the GM parts supplier.
thanks.
How difficult is it to replace the TPS? I just ordered one from the GM parts supplier.
thanks.
LMP
03-04-2010, 11:47 AM
No experience with the 3.4. Naturally, it is bolted to the side of the throttle valve and access can be scarce. Here are a few pictures from the 3.8 installtion.
www.avigex.ca/xport/tps2.jpg
www.avigex.ca/xport/tps3.jpg
www.avigex.ca/xport/maf.jpg but the unit is canted 80° ccw exposing screws
www.avigex.ca/xport/dtc21.jpg
www.avigex.ca/xport/dtc22.jpg
dtc 21/22 in OBD1 relate with OBD2 P0121
www.avigex.ca/xport/tps2.jpg
www.avigex.ca/xport/tps3.jpg
www.avigex.ca/xport/maf.jpg but the unit is canted 80° ccw exposing screws
www.avigex.ca/xport/dtc21.jpg
www.avigex.ca/xport/dtc22.jpg
dtc 21/22 in OBD1 relate with OBD2 P0121
Jrs3800
03-04-2010, 07:38 PM
should not be too bad to change on the 3400... should be 2 screws.. Room may be a tad on the tight side tho..
iceman2
03-05-2010, 09:44 AM
should not be too bad to change on the 3400... should be 2 screws.. Room may be a tad on the tight side tho..
Thanks! LMP and Jrs3800, you guys are the best!
Thanks! LMP and Jrs3800, you guys are the best!
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