1998 V70 AWD P0123 No Shift RESOLVED new TPS

Post by **deepsouth** » 23 May 2014, 19:55

Hey all-
Today on drive home V70 wouldn't shift from 1st or second...rpms would race high but no shift. Only code was a P0123 which is apparently a Throttle Position Sensor code. Anyone had any experience with this issue? Or have values so I can pull the TPS and check it out?
Thanks much!
Eric

Post by **deepsouth** » 24 May 2014, 09:12

Fixed it with a new TPS this morning. Couple of vacuum lines blocked the removal of the old TPS so I removed the inter-cooler hose and IAC Valve, then took off entire throttle body (four 10mm bolts) to gain access. Total fix was around $70 (for the new TPS) and an hour of time. Found an OEM Bosch TPS at PartsGeek for $34 but since it's my daily driver needed it done this morning.

This was the first time I've ever experienced a bad TPS and if I hadn't known better (and read the powertrain code) I would have thought it to be a transmission problem. Engine would race but not shift gears--pegging out the RPM's in second gear. Couldn't get above 30 miles per hour.

Eric

Post by **abscate** » 24 May 2014, 09:49

Thanks for followup Eric...did you get any diagnostics on the bad TPS we can document?

Sorry we couldn't help, but you were on a mission to fix....

Post by **osman** » 24 May 2014, 12:54

It didnt thow a OBD II code for that?

Post by **deepsouth** » 25 May 2014, 10:36

abscate wrote:did you get any diagnostics on the bad TPS we can document?

I did. TPS has three wires coming from it. Middle is input and outer two output. Normal resistances between pins 1 and 3 at idle should range from .7 to 1.4 Ω. Wide open throttle around 1.8 to 2.4 Ω.

For DC voltage: at idle should read .5 volts and--upon opening throttle--steadily climb to around 4.7 volts.

My old one was nowhere near these specs. It started out at .5 volts but the as I'd open the throttle it would jump from 1.5 to 6.2 and then everywhere in between.

Eric

Post by **deepsouth** » 25 May 2014, 10:43

osman wrote:It didnt thow a OBD II code for that?

It did: a P0123. My point was more that I wouldn't have expected a bad TPS to mimic transmission failure. Car would start and idle just fine, but the shift points were completely screwed up causing it to not shift out of second gear. When I applied more gas at 30 mph, the RPMS would peg without shifting, almost like it was in neutral. The only symptoms were erratic shift points/no shift.

Eric

Post by **erikv11** » 25 May 2014, 10:52

Yeah, good info here.

Remember you don't actually "apply gas" you "apply throttle." The ECU decides how much fuel to give the injectors by trying to match the amount of throttle (air) being provided. That air/throttle info comes from the TPS.

I have also had one TPS failure that gave symptoms that seemed like a trans issue. It was more akin to mild slipping though, not like deepsouth witnessed here. It is common for a TPS failure to give both the flashing arrow and the CEL.

roodtz · Post by **roodtz** » 09 Jul 2014, 14:07

Hi Deep South
Many thanks for your info. I had the same problem with my 1998 C 70 and new TPS sorted it out. So grateful, keep up the good work. John Lusaka, Zambia :