p1870(AAARRGGHHH)

[ryknow585]

My tranny hates me! I got code p1870 and p1810, no second gear, this sucks, every vehicle I get gets farcked up, anyone have suggestions or an account of the sucessfulness of the corrective shift kit for p1870. :mad: [img]graemlins/thumbsdown.gif[/img]

[PewterBird]

Hope this helps out some, it sounds like to me that you may have a leak in you tranny fluid and it is causing you to have low pressure creating slippage, that triggers th p1870 code, and that will also trigger the p1810 code.

The powertrain control module (PCM) monitors the torque converter clutch (TCC) slip speed. The PCM calculates the difference between the engine speed and the transmission output speed. In D3 drive range with the TCC engaged, the engine speed should closely match the transmission output speed.

When the PCM detects excessive slip of the TCC, the forward clutch, and the direct clutch when the TCC is engaged in 3rd gear, then DTC P1870 sets. DTC P1870 is a type B DTC.

Possible causes

Low fluid level may be causing the slipping.

Low line pressure may be causing the slipping.

As for the p1810 --------------------------


Circuit Description
The automatic transmission fluid pressure (TFP) manual valve position switch consists of six pressure switches. Five of the switches are normally-open, and determine gear range selection. The sixth switch is normally-closed, and detects torque converter clutch (TCC) release fluid pressure. The TFP manual valve position switch also contains the automatic transmission fluid temperature (TFT) sensor. These components are combined into one unit, mounted on the valve body.

The PCM provides battery voltage on the three range signal circuits. By grounding one or more of the switches with fluid pressure from the manual shift valve, the PCM detects the selected gear range. When you disconnect the transmission electrical connector and the ignition is ON, the ground potential for three range signals from the PCM will be removed, and an illegal gear will be indicated. Refer to the Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic table.

When the PCM detects any of the following conditions, DTC P1810 sets.

An invalid gear state
A drive range after start up
An incorrect gear ratio
DTC P1810 is a type B DTC.

Conditions for Running the DTC
The engine is running.
The system voltage is 8-18 volts.
Conditions for Setting the DTC
One of the following three cases occurs:

Case 1
The gear range is illegal for 60 seconds (Refer to the Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic table).

Case 2
No VSS DTCs P0502 or P0503.
The engine speed is in transition from 0 RPM to greater than 600 RPM.
The vehicle speed is less than 3 km/h (2 mph).
D2, D4 or Reverse gear is indicated after start-up for 2 seconds.
Case 3
No TP DTCs P0121, P0122, or P0123.
No VSS DTCs P0502 or P0503.
No A/T ISS DTCs P0716 or P0717.
No shift solenoid DTCs P0751, P0753, P0756 or P0758.
The vehicle speed is greater than 8 km/h (5 mph).
The TP is greater than 10%.
Engine torque is greater than 14 N·m (10 lb ft).
All of the above conditions are met and one of the following occurs for 5 seconds:
The TFP manual valve position switch indicates PARK/NEUTRAL when the gear ratio is less than 0.72:1 (4th gear).
The TFP manual valve position switch indicates REVERSE when the gear ratio is greater than 2.23:1, or less than 2.02:1.
The TFP manual valve position switch indicates D4, D3, D2 or D1 when the gear ratio indicates REVERSE.
Action Taken When the DTC Sets
The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
The PCM elevates line pressure.
The PCM assumes a D4 shift pattern.
The PCM freezes shift adapts from being updated.
The PCM stores DTC P1810 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.
Conditions for Clearing the MIL/DTC
The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
A scan tool clears the DTC from PCM history.
The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.
Diagnostic Aids
A pressure regulator problem could set DTC P1810.
Inspect the wiring at the PCM, the transmission 20-way connector and the TFP manual valve position switch 6-way connector for the following conditions:
A backed out terminal
A damaged terminal
Reduced terminal tension
A chafed wire
A broken wire inside the insulation
Moisture intrusion
Corrosion
When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step tests the indicated range signal to the manual valve range actually selected.

This step tests for correct voltage from the PCM to the transmission 20-way connector.

This step tests for a short together between circuits 1224, 1225 and 1226.

DTC P1810 TFP Manual Valve Position Switch Assembly Circuit Malfunction Step
Action
Value(s)
Yes
No

1
Was the Powertrain On-Board Diagnostic (OBD) System Check performed?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check

2
Perform the following inspections:

Ensure the transmission linkage from the select lever to the manual valve is adjusted properly.
Perform the Transmission Fluid Checking Procedure .
Are the inspections complete?
--
Go to Step 3
--

3
Install the Scan Tool .
Turn the ignition switch to the RUN position.

Important
Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM.


Record the Freeze Frame and Failure Records.
Clear the DTCs.
While the engine is idling at the normal operating temperature, apply the brake pedal.
Select each transmission range: P, R, N, D4, D3, D2 and D1.
Does each selected transmission range match the scan tool TFP Switch A/B/C display?

Refer to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic .
--
Go to Diagnostic Aids
Go to Step 4

4
Turn the ignition switch OFF.
Disconnect the transmission 20-way connector (additional DTCs may set).
Install the J 39775 jumper harness on the engine side of the transmission 20-way connector.
Turn the ignition switch to the RUN position.
Using the J 35616-A connector test adapter kit and the J 39200 digital multimeter (DMM), inspect for voltage at connector terminals N, R and P.
Is B+ displayed on all three circuits?
--
Go to Step 6
Go to Step 5

5
Inspect the circuits that did not indicate B+ for an open or a short to ground.

Refer to General Electrical Diagnosis Procedures in Wiring Systems.

Was a condition found?
--
Go to Step 7
Go to Step 8

6
Verify that circuits 1224, 1225 and 1226 are not shorted together. Use a fused jumper wire to ground each circuit individually while monitoring the scan tool TFP Switch A/B/C display.

When a range signal circuit is grounded, are any other range signal circuits affected?
--
Go to Step 7
Go to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Resistance Check

7
Repair the wiring as necessary.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?
--
Go to Step 9
--

8
Replace the PCM.

Refer to PCM Replacement/Programming in Engine Controls.

Is the replacement complete?
--
Go to Step 9
--

9
Perform the following procedure in order to verify the repair:

Select DTC.
Select Clear Info.
Operate the vehicle under the following conditions:
Start the vehicle and idle for 3 seconds.
Drive the vehicle in D4 with a TP angle greater than 10%.
Allow the transmission to shift through all gears.
Select Specific DTC. Enter DTC P1810.
Has the test run and passed?
--
System OK
Go to Step 1


© Copyright General Motors Corporation. All Rights Reserved.

[ June 23, 2003: Message edited by: PewterBird ]</p>

[Nachius]

http://www.kdsperformance.com/transhifkits1.html

[SLOWBRAEATER]

If you do a search you will see MANY cases with the 1870 code and how me and everyone else got it to go away. mine was a bad converter, i first tried the easiest cheapest route and that was to have the tranny shop put a different spring in the valve body, one shop wanted to drill but the other guy said it is costly and pretty much worthless. i got the new converter and it went away.

[ryknow585]

slowbra i read your post and a few others but a big difference between mine and all the others is I have no second gear any more. It wont shift, the rpms get up then I have to let of the accelerator and let it drop to 3rd or od

[SLOWBRAEATER]

The first time my one friend wanted to change my tranny filter i started the car and had a ses light. the car wouldnt shift out of first, it was under warranty and the dealer said it was a shift solenoid.

[Guardsman]

I bet I know what the problem is :D .
Has your torque converter clutch been reluctant to stay locked up?
At low speed and part throttle, has your trannys been shifting from 1st to 2nd so hard that it feels like you're getting rear-ended?
When the tranny is shifting hard, do you hear a whistling noise from under the car?
If you have these symptoms, you're the proud owner of a leaking pulse-width-modulated (pwm) torque converter clutch (tcc) apply valve.
See, GM added this wonderful pwm feature back around '95, because joe public couldn't handle the bump when his tcc engaged. So, GM developed the pwm apply valve.
With the old style, the apply valve simply engages, causing the tcc to lock up (good).
With the new style (pwm), the apply valve is modulated, so that it applies increasing pressure, to ever so gently apply the tcc. Thus, no bump.
The problem is, there is a problem with the valve body (that GM knows about), and over time, the apply valve starts to develop a leak. With this leak, the apply valve can't maintain enough pressure to keep the tcc locked up. Consequently, the tcc begins to slip, which creates large amounts of heat. Also, when the slip and heat get bad enough, the PCM commands maximum line pressure to remedy the problem (the rear-ended like shifts).
To fix the problem, you have one of three options.
1) You can get a GM replacement transmission, in which case you'll likely end up with the same problem down the road, not to mention inhereting the other problems that the transmission already has.
2) You can get a mod kit that eliminates the pwm apply, and converts to a straight on-off lock-up. Superior Transmission www.superior-transmission.com makes the kit, and a couple of other companies may also make them. It will require pulling the pan, removing the apply pwm solenoid and the valve, reaming the valve bore, and installing the new parts. The valve is in the valve body.
3) You can do what I did, which was get the transmission rebuilt. I did this 1) because I wasn't sure of the state of the transmission internals at that point, and I didn't want to blow the money on fixing it, and then have the guts let go on me, and 2), I wanted to add a corvette solenoid, shift kit, etc., and, again, I didn't want to install $500 worth of parts, only to have the trans die on me.
When the tranny shop took my transmission apart, the torque converter was fried, the guy said that he tried applying the tcc with air pressure, but there was nothing left to apply. The torque converter case was discolored from the heat. The Redline Hi-Temp transmission fluid that I had installed about 10,000 or so miles before (I flushed the system and put in all new fluid) was torched brown. This fluid is designed to withstand significantly more heat than regular non-synthetic and many synthetic fluids.
The guy and the shop said that the internals (clutches, band, etc.) were still together, but it was only a matter of time before something gave up.
Basically, I would advise you to suck up the money now, and get a good rebuild done on the transmission. You will end up with a trans that shifts better and will last longer than anything you will get from GM. The basic transmission design is good, but they are built like **** from the factory.
E-mail me if you have any more questions on it. streetgang52@hotmail.com