1999 DODGE RAM sensor

Governor pressure is monitored electronically and is used to
control transmission shifting. Electronic control system consists of
Powertrain Control Module (PCM), governor pressure solenoid, governor
pressure sensor, transmission fluid temperature sensor, OD (Overdrive)\
OFF switch, Throttle Position (TP) sensor and output shaft speed
sensor.
NOTE: Governor pressure sensor may also be referred to as governor
pressure transducer. Transmission fluid temperature sensor
may also be referred to as transmission fluid temperature
thermistor. Output shaft speed sensor may also be referred to
as transmission shaft speed sensor or shaft speed sensor.
Transmission shifting is controlled by throttle pressure and
governor pressure. Governor pressure is generated by electronic
components through control of line pressure. Transmission will not
upshift into 4th gear under the following conditions:
* 3rd gear upshift is not complete.
* OD OFF switch is in OFF position.
* Throttle is at 3/4 to WOT position.
* Vehicle speed is too low for 3-4 upshift.
* Transmission fluid temperature is less than 50
F (10C) or
greater than 250F (121C).
* Battery temperature is less than 5F (-15C).
OPERATION
POWERTRAIN CONTROL MODULE (PCM)
The PCM controls Torque Converter Clutch (TCC) operation,
overdrive clutch operation and the governor pressure solenoid. The PCM
determines shift points and TCC operation based on input signals
received from transmission fluid temperature sensor, output shaft
speed sensor, Crankshaft Position (CKP) sensor, Vehicle Speed Sensor
(VSS), Throttle Position (TP) sensor and battery temperature sensor.\
There are 4 governor pressure curves programmed into the PCM.
Governor pressure curves allow the PCM to adjust governor pressure for
varying conditions. One governor pressure curve is used for operation
when transmission fluid temperature is at or less than 30
F (1C). The
second governor pressure curve is used for operation when transmission
fluid temperature is at or greater than 30
F (1C) during normal city
operation or highway driving. The third governor pressure curve is
used for operation during wide open throttle (WOT). The fourth
governor pressure curve is used for operation when transfer case is in
low range.
The PCM controls TCC operation by operating the lock-up
solenoid located on the valve body. Lock-up solenoid may be referred
to as TCC solenoid. If OD switch is in the ON position, the TCC will
lock-up once transmission is in 4th gear with vehicle speed greater
than 45 MPH. If OD switch is in the OFF position, the TCC will lock-up
once transmission is in 3rd gear with vehicle speed greater than 35
MPH at light throttle application. When OD switch is in the OFF
position, the OD light on instrument panel will be illuminated.
The PCM prevents TCC operation and overdrive operation when
transmission fluid temperature is less than 50
F (10C). If
transmission fluid temperature exceeds 260F (126C), the PCM will
cause a 4-3 downshift and engage the TCC. The OD light will be
illuminated when the downshift occurs. Transmission will not upshift
until transmission fluid temperature decreases to approximately 230
F
(110F).

The PCM contains a self-diagnostic system used for
determining an electronic component failure. The PCM self-diagnostic
system will store a Diagnostic Trouble Code (DTC) in PCM memory if
certain electronic problems are present.
DTCs can be retrieved using appropriate scan tool. See SELF-
DIAGNOSTIC SYSTEM. After repairing an electronic system problem,
stored DTC must be cleared from PCM memory. For PCM location, see PCM
LOCATION table.
AB Body
On firewall, near wiper motor.
AN & DN Bodies
Right front fender, near air cleaner.
BR Body
Right front fender, near firewall.
WJ Body
On firewall, near speed control servo.
GOVERNOR PRESSURE SENSOR
NOTE: Governor pressure sensor may also be referred to as governor
pressure transducer.
Governor pressure sensor delivers an output signal to the PCM
indicating the output pressure of governor pressure solenoid. The PCM
uses this signal to control governor pressure. Governor pressure
solenoid is located on valve body. See Fig. 1.
GOVERNOR PRESSURE SOLENOID
Governor pressure solenoid generates governor pressure
required for transmission upshifts and downshifts. Governor pressure
solenoid is located on valve body. See Fig. 1. Inlet side of governor
pressure solenoid is exposed to normal transmission line pressure and
outlet side provides a passage to governor circuit in the valve body.
Governor pressure solenoid regulates transmission line pressure to the
governor circuit. Electrical supply voltage is supplied to governor
pressure solenoid by PCM. The PCM controls the ground circuit to
governor pressure solenoid to provide solenoid operation.
Fig. 1: Identifying Governor Pressure Solenoid, Governor Pressure
Sensor & Transmission Fluid Temperature Sensor
Courtesy of DaimlerChrysler Corp.
OD (OVERDRIVE) OFF SWITCH

The OD (Overdrive) OFF switch is located on instrument panel,\
to the right of steering column. The OD OFF switch controls overdrive
operation by delivering an input signal to PCM. The PCM uses this
signal for controlling operation of overdrive solenoid on the valve
body.
When overdrive switch is in the OFF position, OD light on
instrument panel will be illuminated and transmission will not upshift
into 4th gear for overdrive operation. When OD switch is in the ON
position, OD light on instrument panel will not be illuminated and
transmission will upshift into 4th gear for overdrive operation.
If OD switch is in the ON position, the TCC will lock-up when
transmission is in 4th gear with vehicle speed greater than 45 MPH. If
overdrive switch is in the OFF position, the TCC will lock-up when
transmission is in 3rd gear with vehicle speed greater than 35 MPH at
light throttle application.
THROTTLE POSITION (TP) SENSOR
The TP sensor delivers an input signal to the PCM to indicate
throttle position. The PCM uses this input signal for controlling TCC
operation, governor pressure and upshift into 4th gear for overdrive
operation.
TRANSMISSION FLUID TEMPERATURE SENSOR
NOTE: Transmission fluid temperature sensor may also be referred to
as transmission fluid temperature thermistor or transmission
fluid temperature sender.
Transmission fluid temperature sensor delivers an input
signal to the PCM to indicate transmission fluid temperature. The PCM
uses this input signal for controlling the TCC, overdrive operation
and governor pressure. Transmission fluid temperature sensor is
located on the valve body and is integral with governor pressure
sensor. See Fig. 1.
OUTPUT SHAFT SPEED SENSOR
NOTE: Output shaft speed sensor may also be referred to as
transmission shaft speed sensor or shaft speed sensor.
Output shaft speed sensor is located on overdrive unit
attached to rear of transmission. Output shaft speed sensor is mounted
above the lugs on park gear in the overdrive unit. Speed sensor input
signals are generated when lugs on park gear rotate past face of
sensor. Input signals are delivered to PCM. The PCM uses this input
signal for controlling transmission operation. The Vehicle Speed
Sensor (VSS) also serves as a back-up to the output shaft speed
sensor. The VSS signal is also an input to the PCM.
TROUBLE SHOOTING
* PLEASE READ THIS FIRST *
NOTE: For symptom trouble shooting, see appropriate AUTOMATIC
TRANSMISSION OVERHAUL article.
PRELIMINARY INSPECTION
Visually inspect all electrical wiring, looking for chafed,

stretched, cut or pinched wiring. Ensure electrical connectors fit
tightly and are not corroded. Check PCM, sensors and switches for
physical damage. Check engine coolant level. Check transmission fluid
level and condition.
SELF-DIAGNOSTIC SYSTEM
* PLEASE READ THIS FIRST *
NOTE: Only transaxle-related trouble codes are listed. For engine-
related DTC definitions, see TROUBLE CODE DEFINITIONS article
in APPLICATIONS & IDENTIFICATION. For engine-related DTC
diagnosis, see appropriate SELF-DIAGNOSTICS article in ENGINE
PERFORMANCE. Engine performance DTCs must be repaired first,
as engine performance and related component signals will
affect transaxle operation and diagnosis.
DIAGNOSTIC PROCEDURE
When performing vehicle diagnosis:
* Ensure transmission fluid level is correct and fluid is
neither contaminated or aerated.
* Ensure shift cable is properly adjusted. See appropriate
AUTOMATIC TRANSMISSION SERVICING article in TRANSMISSION
SERVICING.
* Ensure battery is fully charged.
* Perform visual inspection, ensuring all electrical
connections at transmission, PCM, TP sensor and output shaft
speed sensor are clean and properly installed.
* Retrieve DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES.
* Repair DTCs in order displayed.
* Always perform test verification test after any repair
procedure is completed unless specified otherwise. See
appropriate verification test under DIAGNOSTIC TESTS.
NOTE: Self-diagnostic tests are written specifically for Chrysler's
Diagnostic Readout Box (DRB) scan tool. A generic scan tool
may be used, but may not be capable of performing all
necessary test functions.
TEST EQUIPMENT HOOK-UP
Generic Scan Tool & DVOM
Self-diagnostic tests are written specifically for Chrysler's
Diagnostic Readout Box (DRB) scan tool. The DRB has a built-in DVOM
function. A generic scan tool may be used, but may not be capable of
performing all necessary test functions. If DRB test procedures
require resistance or voltage to be measured using scan tool in
ohmmeter or voltmeter mode, connect DVOM ground lead to DLC connector
terminal No. 4 and positive lead to terminal specified in test
procedure.
DRB Scan Tool
Refer to DRB scan tool instructions to read and clear DTCs,
and when performing other scan tool functions. DRB scan tool is
grounded through DLC connector terminal No. 4. Only one volt/ohmmeter
test lead is required to measure voltage or resistance. See Fig. 2.
RETRIEVING DIAGNOSTIC TROUBLE CODES
NOTE: Manufacturer recommends using Chrysler's Diagnostic Readout

Box (DRB) scan tool with appropriate cartridge for system
diagnosis. Other after-market scan tools may be used for
system diagnosis. The following procedure is for DRB scan
tool usage. Use scan tool manufacturer's instruction for
operating scan tool.
NOTE: Ensure battery is fully charged before proceeding with test.
1) Ensure ignition is off. Connect DRB to Data Link Connector
(DLC) located under driver's side of instrument panel. Using scan
tool, display all Diagnostic Trouble Codes (DTCs). Identify DTCs once
retrieved. See DIAGNOSTIC TROUBLE CODES (DTC) & DRB MESSAGES table.
2) If scan tool will not power up, check for loose cable
connections or faulty cable. If cable connections and cable are okay,
check voltage at DLC terminal No. 16. Voltage should be at least 11
volts. If voltage is not as specified, check wiring circuit and
necessary fuses. See WIRING DIAGRAMS.
3) If scan tool displays an error message, RAM TEST FAILURE,
CARTRIDGE ERROR, KEY PAD TEST FAILURE, or LOW OR HIGH BATTERY, this
indicates a scan tool failure.
4) If DTCs are displayed, perform appropriate test(s). See
DIAGNOSTIC TROUBLE CODES (DTC) & DRB MESSAGES table. If no DTCs are
displayed, see TROUBLE SHOOTING in appropriate AUTOMATIC TRANSMISSION
OVERHAUL article.
DIAGNOSTIC TROUBLE CODES (DTC) & DRB MESSAGES









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DTC DRB-III Scan Tool Message
P0711 .................. TRANS TEMP SENSOR, NO TEMP RISE AFTER START
P0712 ............................. TRANS TEMP SENSOR VOLTAGE TO LOW
P0713 ............................ TRANS TEMP SENSOR VOLTAGE TO HIGH
P0720 ..................... LOW OUTPUT SPEED SENSOR RPM ABOVE 15 MPH
P0740 .................... TORQ CONVERTER CLU, NO RPM DROP AT LOCKUP
P0743 ........ TORQUE CONVERTER CLUTCH SOLENOID/TRANS RELAY CIRCUITS
P0748 ........... GOVERNOR PRESSURE SOL CONTROL/TRANS RELAY CIRCUITS
P0751 ....................... OD SWITCH PRESSED (LO) MORE THAN 5 MIN\
P0753 ................ TRANS 3-4 SHIFT SOLENOID/TRANS RELAY CIRCUITS
P0783 ....................... 3-4 SHIFT SOL, NO RPM DROP @ 3-4 SHIFT
P1740 (1) .......................... TCC OR O/D SOLENOID PERFORMANCE
P1756 .................... GOV PRESS NOT EQUAL TO TARGET @ 15-20 PSI
P1757 ...................... GOV PRES ABOVE 3 PSI IN GEAR WITH 0 MPH
P1762 .................... GOV PRESS SEN OFFSET VOLTS TO LOW OR HIGH
P1763 ....................... GOVERNOR PRESSURE SENSOR VOLTS TO HIGH
P1763B ...................... GOVERNOR PRESSURE SENSOR VOLTS TO HIGH
P1764 ........................ GOVERNOR PRESSURE SENSOR VOLTS TO LOW
P1765 ..................... TRANS 12 VOLT SUPPLY RELAY CNTRL CIRCUIT
P1899 .......................... P/N SWITCH STUCK IN PARK OR ON GEAR
( 1) - BR body only.









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CLEARING DIAGNOSTIC TROUBLE CODES
After repairs have been performed, clear DTCs from PCM memory
using scan tool, following scan tool manufacturer's instructions.
NOTE: If malfunction is no longer present after DTC is stored in
PCM memory, the PCM will erase DTC after ignition has been
cycled at least 50 times. DTC may be cleared by using scan
tool. Follow scan tool manufacturer's instructions. DTCs may
also be cleared by disconnecting negative battery cable for a
period of time, but other vehicle control modules may also be

affected.
INACTIVE DTC CONDITION
This procedure applies if you have been sent here from a
diagnostic test and/or have just attempted to simulate the condition
that initially set the DTC. The following additional checks may assist
in identifying a possible intermittent problem:
* Visually inspect related wiring harness connectors for
broken, bent, pushed out or corroded terminals.
* Visually inspect related wiring harnesses for chafed, pierced
or partially broken wires.
* Check for Technical Service Bulletins (TSBs) relating to the
problem.
NOTE: For circuit description and wire color information, see
WIRING DIAGRAMS.
CONNECTOR IDENTIFICATION
CONNECTOR IDENTIFICATION DIRECTORY








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Connector Figure
Data Link Connector (DLC) ............................... See Fig. 2
Overdrive (O/D) Off Switch
AN, BR & DN Bodies .................................... See Fig. 3
WJ Body ............................................... See Fig. 4
Park/Neutral Position (PNP) Switch ...................... See Fig. 5
Powertrain Control Module (PCM) ......................... See Fig. 6
Transmission Control Relay
AB Body ............................................... See Fig. 7
AN, BR, DN & WJ Bodies ................................ See Fig. 8
Transmission Governor Pressure Sensor ................... See Fig. 9
Transmission Output Shaft Speed Sensor
AB, BR & WJ - 4.0L Bodies ............................ See Fig. 10
AN & DN Bodies ....................................... See Fig. 11
Transmission Solenoid .................................. See Fig. 12









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Fig. 9: Identifying Transmission Governor Pressure Sensor
Connector Terminals
Courtesy of DaimlerChrysler Corp.
Fig. 10: Identifying Transmission Output Shaft Speed Sensor
Connector Terminals (AB, BR & WJ Bodies)

Courtesy of DaimlerChrysler Corp.
Fig. 11: Identifying Transmission Output Shaft Speed Sensor
Connector Terminals (AN & DN Bodies)
Courtesy of DaimlerChrysler Corp.
Fig. 12: Identifying Transmission Solenoid Connector Terminals
Courtesy of DaimlerChrysler Corp.
DIAGNOSTIC TESTS