Thread: Trans. Codes: P0730, P1810 Sell car? Flush Fluid?

I have a Silver 01 2 door Grand Prix GTP I bought in June. Body and interior is flawless. $4,500 into it (engine went out on day 1). Have been driving it 70 miles a day for a month. 126K miles.

Have been driving it like a grandpa the whole time with the exception of yesterday. I did a short race (10-80 mph, no wheelspin, and then backed off) Shifted just fine and did great.

This morning I noticed a check engine light:
1. Oxygen Sensor
2. P0730 "Gear Ratio Incorrect"
3. P1810 "Tranny Fluid Pressure Valve Position Switch"

Still shifts nice and smooth, ZERO signs of slippage or anything. The fluid is fairly dirty looking and about a 1/4" above the full mark. It's always been real smooth when I shift into drive, but I've always noticed when I shift into reverse. Not really a thump, just slightly different than drive and you can feel it a little.

I really like the car and it's about the best I've ever had. It was bought for a DD and I have a family and can't afford for the transmission to go out on me as things are pretty tight, and I already got screwed with the engine.

What I'm really needing here is some good advice as how to proceed. Have the fluid machine flushed with cleaner? Sell the car? Keep driving as is? Do you all think the transmission is on the way out the door? I could park it until it sold if I went that route. I'm gonna try to reset the computer before the 35 mile drive home and see if the light comes back.

Thanks all.













P1810
Possible causes
- Faulty automatic Transmission Fluid Pressure (TFP) Manual Valve Position Switch
- TFP Valve Position Switch harness is open or shorted
- TFP Valve Position Switch circuit poor electrical connection
What does this mean?

When is the code detected?
When the Powertrain Control Module (PCM) detects an invalid state of the Transmission Fluid Pressure (TFP) manual valve position switch circuit by deciphering the TFP manual valve position switch inputs, then the P1810 code sets.
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P1810 Chevrolet Description
The automatic Transmission Fluid Pressure (TFP) manual valve position switch consists of five pressure switches (two normally-closed and three normally-open) and a Transmission Fluid Temperature (TFT) sensor combined into one unit. The combined unit mounts on the valve body.
The Powertrain Control Module (PCM) supplies ignition voltage for each range signal. By grounding one or more of the circuits through various combinations of the pressure switches, the PCM detects which manual valve position you select. The PCM compares the actual voltage combination of the switches to a TFP manual valve position switch combination table stored in memory.
The TFP manual valve position switch cannot distinguish between PARK and NEUTRAL because the monitored valve body pressures are identical. With the engine OFF and the ignition switch in the RUN position, the TFP manual valve position switch indicates PARK or NEUTRAL. Disconnecting the AT inline 20-way connector removes the ground potential for the three range signals to the PCM. In this case, with the engine OFF, and the ignition switch in the RUN position, D2 will be indicated.



P0730

Possible causes
- Low transmission fluid level
- Dirty transmission fluid
- Shift solenoids
- Transmission mechanical problems
- Transmission hydraulic control circuit
What does this mean?

Tech notes
Start by inspecting the transmission fluid level and condition, and change fluid if necessary.
What does this mean?

When is the code detected?
The TCM has detected that the transmission is trying to mechanically shift to a lower gear than intended
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Incorrect transmission shifting
P0730 Description
This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by Transmission Control Module (TCM) as follows:
Torque converter slip ratio = A x C/B
A: Output shaft revolution signal from speed sensor (revolution sensor)
B: Engine speed signal from Engine Control Module (ECM)
C: Gear ratio determined as gear position which TCM supposes
If the actual gear position is higher than the position supposed by TCM, the slip ratio will be more than normal. In case the ratio exceeds the specified value, TCM judges this diagnosis malfunction.

First place I went. when I first wrote the post, was Advance. Went by OReilly's to have them clear the Code and read it while they were at it. Only showed bank 1 code! Says it's running rich. Didn't list the trans. codes. Cleared it out.

Next day (today) SES light back on. When I passed a car and gave it some pedal.

Back to O'Reilly's. Same bank 1 code. P0172. No trans codes. Maybe the trans is ok.

A little scary after reading through the forum. Reading stuff like "it's just a matter of time before 4th gear goes out with these transmissions", etc. is enough to freak a guy out.