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AZ_HUNTER, GM World Class Tech
Category: Chevy
Satisfied Customers: 401
Experience:  16 years GM Tech, ASE Master Certified
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i have a 2000 4wd with a 4l60e has a code 4 p1810 wont go

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i have a 2000 4wd with a 4l60e has a code 4 p1810 won't go in to gear but when it does it it is fine

the most likley cause is the transmission fluid pressure valve switch. It is located

under the transmision pan on the valve body. If you have an ohm meter you can remove

the switch assembly and check each individual switch on the assembly. On the under side of the switch you will see multiple "plunger" switches. PLace the leads of the meter

on each side of the "plunder" switch contacts (little rivots) and press the plunger down with the eraser end of a pencil. Most of the switched will be open till pressed with one or

two being colsed until pressed Hope this helps...

Customer: replied 8 years ago.
what about ignition switch

There would be other codes stored. What engine do you have and in what vehicle?


Customer: replied 8 years ago.
5.3 when i does go in it's fine. no slip goes great

When it acts up, does it move? it hould defalt to 3rd gear. you may have an issue with

a valve hanging up in the valve body. no other codes stored in the computer?

Customer: replied 8 years ago.
no other codes. it won't move if u start it and go forward 20 feet then stop and put it into park after that no forward or reverse .had remote start on it but i removed and fix all wires. when it won't move u let it idle 4 20 minutes and it is fine. changed filter a t-tec it twice.
It sounds like an internal pressure problem mot likley with the valve body. Also make sure the fluid level is correct.
Customer: replied 8 years ago.
you don't have a clue do you

The trans. pressure switch is a multiswitch assembly which tell the computer which

gear it is in. Without pressure, no switch activation. This is why I think you may have an internal presure loss issue. The first step is to make sure the fluid level is correct. If you have a scan tool, you need to verify whether or not the switch data is correct while the condition is present. Is there any abnormal noises from the transmission while the condition is present? I am doing the best I can without actually putting my hands on the vehicle.

Customer: replied 8 years ago.
no noises ,tranny full, pressure great. some times it moves fine other times u have to wait. no slip, doesen't even try. then it like a light switch it on. the display for the PRND321 dosen't seem to indicate some times either

Here is a wiring schmatic for the pressure switch involved. Check the ignition power

circuits while the condition is present. This will rule out the power loss. When you say pressure is great, you checked it with a gauge correct? Do you recall the pressures?

Object Number: 525079  Size: LF

Customer: replied 8 years ago.
can't see wire diagram sorry. put relay in e terminal dr blue wire to voltage
This obviouly didn't happen right after the filter change did it? Does it happen all the time after it sits say over night? So many posiblities.
Highlight schmatic, right click and copy, paste it in a word doc. and enlarge it.

Here is the connector end view at the trans...

Object Number: 529775  Size: CH
Click here for detailed picture of above image.

Connector Part Information

Engine Harness Side 20 Way F Micro-Pack 100 W Series (GRY)


Wire Color

Circuit No.





1-2 Shift Solenoid Valve Control




2-3 Shift Solenoid Valve Control




Pressure Control (PC) Solenoid Valve Controlled Power




PC Solenoid Valve Controlled Ground




Transmission Solenoid Power




Not Used




Transmission Fluid Temperature (TFT) Sensor Signal




TFT Sensor Ground (4.3L)




TFT Sensor Ground (4.8L and 5.3L)




TFP Switch Signal A




TFP Switch Signal C




TFP Switch Signal B




3-2 Shift Solenoid Valve Assembly Control




Torque Converter Clutch Solenoid Valve Control




Torque Converter Clutch Pulse Width Modulation Solenoid Valve Control




Not Used


Customer: replied 8 years ago.
sorry it took so long for a reply hope u are still out there. changed tfp solenoid. check to make sure i had power to e terminal i do. code p1810 came back up but not as quick took a few key cycles. transmission moves fine. hanen't let it sit long enough to try. also have a p0449 evap code don't think it has anything to do with it but i am at a lose any ideas where do i go from here

Ok, you replaced the fluid pressure solenoid, but not the pressure manifold switch assembly? I may have misled you with my first terminology. The code is for the manifold switch, or transmission fluid pressure manual valve position switch. This is a pic and description:


Object Number: 650544  Size: SH
Click here for detailed picture of above image.

Important: Seven valid combinations and two invalid combinations are available from the TFP manual valve position switch. Refer to the Transmission Fluid Pressure Manual Valve Position Switch Logic table for valid/invalid combinations for range signal circuits A, B and C.

The transmission fluid pressure (TFP) manual valve position switch consists of five pressure switches (two normally-closed and three normally-open) on the control valve body that sense whether fluid pressure is present in five different valve body passages. The combination of switches that are open and closed is used by the PCM in order to determine the actual manual valve position. The TFP manual valve position switch, however, cannot distinguish between PARK and NEUTRAL because the monitored valve body pressures are identical in both cases.

The switches are wired to provide three signal lines that are monitored by the PCM. These signals are used to help control line pressure, torque converter clutch apply and shift solenoid valve operation. Voltage at each of the signal lines is either zero or twelve volts.

In order to monitor the TFP manual valve position switch operation, the PCM compares the actual voltage combination of the switches to a TFP combination table stored in its memory.

The TFP manual valve position switch signal voltage can be measured from each pin-to-ground and compared to the combination table. On the automatic transmission (AT) wiring harness assembly, pin N is signal A, pin R is signal B, and pin P is signal C. With the AT wiring harness assembly connected and the engine running, a voltage measurement of these three lines will indicate a high reading (near 12 volts) when a circuit is open, and a low reading (zero volts) when the circuit is switched to ground.

The transmission fluid temperature (TFT) sensor is part of the TFP manual valve position switch assembly.

Customer: replied 8 years ago.
is the pressure maifold switch hard to change?

Very easy, remove trans. pan and it is right there. 2 short bolts and 3 long bolts (5 total).

Do not over tigten these bolts. only should be 6 to 10 ft. pounds.

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