The automatic transmission fluid pressure (TFP) manual valve position switch assembly consists of two normally-open pressure switches. The assembly is attached to the lower control valve body. The PCM supplies ignition voltage on the two range signal circuits, signal circuit A and signal circuit C. By grounding one of the switches with fluid pressure from the manual valve, the PCM detects a garage shift from PARK/NEUTRAL to REVERSE or PARK/NEUTRAL to DRIVE (D1, D2, D3, or D4). Refer to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic . This information is used by the PCM in order to adjust line pressure during garage shifts.
Transmission Fluid Pressure Manual Valve Position Switch Logic Range Signal---------------- A------------C
Park/Neutral-----------------HI---------------HI
Reverse--------------------LOW--------------HI
Drive (D1, D2, D3 and D4)----HI--------------LOW
Invalid---------------------LOW-------------LOW
HI = Ignition voltage
LOW=0 voltage
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The transmission internal mode switch (IMS) is a multi-signal switch assembly attached to the lower control valve body. The IMS consists of a set of stationary contacts and a set of sliding contacts. The manual valve link assembly connects the sliding contacts to the manual valve. Electrically, the stationary contacts are connected to ground through the IMS ground circuit and the sliding contacts are connected to the PCM through four IMS signal circuits. The signal voltage at the PCM is high, ignition voltage, when a signal circuit is open and low, 0 volts, when a signal circuit is closed to ground. Each gear selector position grounds one or more of the signal circuits in a unique pattern that enables the PCM to determine gear selector position. Refer to Transmission Internal Mode Switch Logic .
No Power on Heavy Acceleration or 1-2 Shift Concerns - Delays, Slips, Flares, DTC P0731 or P0732 Set (Replace Transmission Fluid Pressure Switch Assembly or Lower Control Valve Body Assembly) #01-07-30-009B - (02/06/2002)
Condition Some owners of the above vehicles with a Hydra-Matic 4T80-E transaxle may comment about no power on heavy acceleration or 1-2 shift concerns such as delays, slips or flares. Cadillac customers with the above models may comment that "Service Transmission" may display on the Driver Information Center (DIC). The technician will note that DTCs P0731 (Incorrect 1st Gear Ratio) and/or P0732 (Incorrect 2nd Gear Ratio) are set.
Cause This condition may be caused by a leaking transmission fluid pressure (TFP) switch assembly (936) that intermittently indicates park/neutral while in drive, during a heavy throttle launch. The Powertrain Control Module (PCM) software will invoke torque abuse protection when park/neutral is indicated with a large throttle opening. Engine torque is then managed causing the transmission input speed to decrease. Since the gear ratio that is calculated is outside of the range of any known gears, a DTC P0731 or P0732 may set.
Hey, I was getting these problems also when my water pump was leaking. I assume it was getting fluid in to the connectors and the controller in front of my driver-side front wheel. It went away when the pump and headgaskets were replaced. He may be on to it there...
The automatic transmission fluid pressure (TFP) manual valve position switch assembly consists of two normally-open pressure switches. The assembly is attached to the lower control valve body. The PCM supplies ignition voltage on the two range signal circuits, signal circuit A and signal circuit C. By grounding one of the switches with fluid pressure from the manual valve, the PCM detects a garage shift from PARK/NEUTRAL to REVERSE or PARK/NEUTRAL to DRIVE (D1, D2, D3, or D4). Refer to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic . This information is used by the PCM in order to adjust line pressure during garage shifts.
Transmission Fluid Pressure Manual Valve Position Switch Logic Range Signal---------------- A------------C
Park/Neutral-----------------HI---------------HI
Reverse--------------------LOW--------------HI
Drive (D1, D2, D3 and D4)----HI--------------LOW
Invalid---------------------LOW-------------LOW
HI = Ignition voltage
LOW=0 voltage
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The transmission internal mode switch (IMS) is a multi-signal switch assembly attached to the lower control valve body. The IMS consists of a set of stationary contacts and a set of sliding contacts. The manual valve link assembly connects the sliding contacts to the manual valve. Electrically, the stationary contacts are connected to ground through the IMS ground circuit and the sliding contacts are connected to the PCM through four IMS signal circuits. The signal voltage at the PCM is high, ignition voltage, when a signal circuit is open and low, 0 volts, when a signal circuit is closed to ground. Each gear selector position grounds one or more of the signal circuits in a unique pattern that enables the PCM to determine gear selector position. Refer to Transmission Internal Mode Switch Logic .
well
ive checked everything
the dealer put on a redundant ground and it seems to of MAYBE fixed the abs, t/c and brake light
but the cluster _ seems worse
now while in D and while in R it flashes
whiles its doing it (i put bricks under the wheels, i tried yanking the shift cable, pushing the shifter all around, it continues to flash
If you have no coolant in the 20 way connector. You should look at this.
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Transmission Internal Mode Switch Logic
Gear Selector Position--------A--------B--------C----------P
Reverse--------------------LOW-----LOW------HI---------HI
Drive 4---------------------HI-------LOW------LOW-------HI
Drive 4/Drive 3-------------LOW----- LOW------LOW-------HI
Drive 3--------------------LOW------LOW------LOW------LOW
If the IMS switch was bad it would have to have 2 circuit go bad simultaneously. Not likely. Hmmmm
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Transmission Fluid Pressure Manual Valve Position Switch Logic
Range Signal----------------- A------------C
Reverse---------------------LOW----------HI
Drive (D1, D2, D3 and D4)-----HI----------LOW
Invalid----------------------LOW---------LOW
The TFPS uses hydraulic pressure to determine the Manual valve location.
Both the TFPS and the IMS are connected to the Manual valve.
The TFPS will cause many low power driveability issues AS I HAVE STATED!
The TFPS is a common failure. It is a switch that will only work if the car is running and that is the difference between it and the IMS. The TFPS has two types. First was used up to 00 and the second was used after 00. Most of the time when you have an TFPS failure you will have a Service trans message and a P0731 or P0732, but it may not set a code.
TSB 01-07-30-009B
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The IPC displays the selected gear position as determined by the PCM. The IPC receives a class 2 message from the PCM indicating the gear position. The PRNDL display blanks if:
• The PCM detects a malfunction in the transmission range switch signal circuit.
• The IPC receives a class 2 message indicating the park position and the column park switch indicates a position other than park.
• The IPC detects a loss of class 2 communications with the PCM.
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You may have a Class II issue like I talked about. If this happens the Tech II would loose comm when it is down. I don't think you would be able to Diag it any other way. You maybe able to check the ClassII line voltage with a DMM, but that would just show if it was shorted to B+ or Ground when it occurs.
The bus will float at a nominal 7 volts during normal operation
the more and more gets limited out the more and more i think your right about the TFPS switch
i did have the service tranny,
every so often ill go to launch it and it feels like its completely bogged down,
now how do i go and prove that this is the problem to get it solved, can i say that i had you diagnose it?
i really appreciate everything AJ
