Automatic Transmission Diagnostic Procedures: Overview Dodge Pickup R2500

IDENTIFICATION OF SYSTEM

The 45RFE/545RFE Transmission family can be identified by confirming the presence of a 23 pin electrical connector on the left-hand side of the transmission oriented vertically near the manual lever. The 243/273 Electronic Transfer Case can be identified by the Transfer Case Identification Tag, confirming the presence of a Shift Motor or the Selector Switch on the dash panel.

GENERAL DESCRIPTION

The 45RFE/545RFE electronic transmission is a conventional transmission in that it uses hydraulically applied clutches to shift a planetary gear train. However, the electronic control system replaces many of the mechanical and hydraulic components used in conventional transmission valve bodies.

The 45RFE/545RFE electronic transmission is a fully electronically controlled transmission. The Transmission Control Module (TCM) is similar to (but not the same as) the one used in the 41TE and 42LE transmissions, therefore many similarities exist in function and diagnosis.

The 45RFE/545RFE has an overrunning clutch (used in 1st gear), an electronically controlled torque converter clutch, 3 planetary gear sets, and six clutch packs. The clutches are called 2nd Clutch (2C), 4th Clutch (4C), Low/Reverse Clutch (LR), Reverse Clutch (RC), Underdrive Clutch (UD), and Overdrive Clutch (OD).

Although the 45RFE is considered a 4 speed transmission, it really has 5 forward gear ratios. The 545RFE is considered a 5 speed transmission, it really has 6 forward gear ratios. 2nd gear (1.67:1) and 2nd prime (1.50:1) gear are so close in ratio that they are not considered to be different gear ratios, although both are used as 2nd gear under certain conditions. During most upshift and downshift maneuvers, 2nd gear will be used. 2nd prime gear is only used for a high speed 4-2 downshift. The 545RFE transmission is essentially a software change to the TCM that allows an additional overdrive ratio of (.667:1). The gear ratio of 4th Prime is achieved by applying the 2C and OD clutches. The 4th Prime is used above 52 MPH. All gear ratios in the 45RFE/545RFE are achieved by applying two elements (clutches). During a shift, one element is released and another is applied, resulting in a different ratio. This is called a clutch to clutch shift. In order to perform a 4-2 downshift, two elements would have to be released and two different elements applied. The 2nd prime gear ratio allows a clutch to clutch 4-2' (2nd prime) downshift.

The oil pump in the 45RFE/545RFE is a dual stage positive displacement gear type pump. At idle and low engine speeds, both stages are working. Once the engine speed reaches a point where one side of the pump can supply the necessary system requirements, the second stage is vented. This pump configuration gives the pressure and flow of a large displacement pump at low speeds, and the economy of a small displacement pump at higher engine speeds. The oil pump housing also contains some of the valves that are found in the valve body in a 41TE or 42LE transmission. The Converter Clutch Switch Valve, Converter Clutch Regulator Valve, Torque Converter Limit Valve, and the Pressure Regulator Valve, are all found in the oil pump housing.

The electronic control system consists of a Transmission Control Module (TCM), a Transmission Range Sensor (TRS), an Input Speed Sensor (ISS), an Output Speed Sensor (OSS), a Line Pressure Sensor (LPS), a Transmission Temperature Sensor (TTS), five pressure switches, and seven solenoids. Each clutch pack has a corresponding solenoid and pressure switch except for the reverse clutch, which is controlled by the manual valve. The other two solenoids are called the Multi Select (MS) solenoid and the Pressure Control Solenoid (PCS).

The PCS is used to control line pressure. The 45RFE/545RFE controls line pressure based on inputs to the TCM. The line pressure is torque based (line pressure increases with torque) most of the time, however it is set to a predetermined value just prior to a shift and reverts back to torque based after the shift.

The MS solenoid is used to control the LR clutch during P-R and N-R garage shifts and to control the OD clutch when the Manual Valve is in the "D" position as reported by the TRS. If the manual valve is slightly out of position, the TRS will indicate a temporary zone (T3 or T4). In this case the OD clutch will be controlled by the OD solenoid. Note that if the TRS indicates a temporary zone, this is a valid PRNDL code and will not set a DTC P0706(28). If the PRNDL code consistently indicates a temporary zone while the shift lever is in the "D" position, this would indicate some sort of mechanical problem in the shift linkage as opposed to an electrical TRS problem. Note: vehicle operation in the T3 temporary zone can set a DTC P1715(65).

The 243/273 Electronic Transfer Case is a conventional transfer case that uses a shift motor to place the transfer case into the desired range. A multi-position switch selector is located on the dash panel in place of a manual shift lever located on the floor.

The Transfer Case shift motor is a bi-directional, 2-wire motor. When the motor is energized, one of the leads is 12-volts and the other is ground. Reversing the polarity of the motor changes the direction of the rotation of the motor. The motor has a low speed, high torque output.

The Transfer Case Mode Sensor consists of a magnetic ring and four Hall Effect transistors that convert the shaft position into a coded signal sent to the TCCM. The magnet forces the output of the Hall device low when it is passed over it. The Mode Sensor is supplied 5 volts and a ground from the TCCM and has four output lines that feed back to the TCCM.

The Transfer Case Selector Switch is a multi-position, multi resistance switch that tells the TCCM what range is commanded. The switch assembly also contains a separate Neutral Button and four indicators, one for each selectable range.

FUNCTIONAL OPERATION

The 45RFE/545RFE electronic transmission has a fully adaptive control system. The system performs its functions based on continuous real-time sensor feedback information. The control system automatically adapts to changes in engine performance and friction element variations to provide consistent shift quality. The control system ensures that clutch operation during upshifting and downshifting is more responsive without increased harshness.

The Transmission Control Module (TCM) continuously checks for electrical problems, mechanical problems, and some hydraulic problems. When a problem is sensed, the TCM stores a diagnostic trouble code (DTC). Some of these codes cause the transmission to go into "limp-in" or "default" mode. The 45RFE/545RFE has three default modes

(I) Immediate shutdown - The TCM de-energizes the transmission control relay. This causes the transmission system to immediately default to third gear if shift lever is in the "D" position, or 2nd gear if it is in the "2" or "L" positions. Park, Neutral, and Reverse are still available.

(O) Orderly Shutdown - If the TCM recognizes a problem that does not require an immediate shutdown, the transmission will maintain the current gear and the transmission control relay will remain energized until de-energizing it will not overspeed the engine. When the vehicle speed reaches a reasonable level the TCM de-energizes the transmission control relay. This causes the transmission system to immediately default to third gear if shift lever is in the "D" position, or 2nd gear if it is in the "2" or "L" positions. Park, Neutral, and Reverse are still available.

(L) Logical Shutdown with Recovery - The TCM does not de-energize the Transmission Control Relay. Instead, the transmission will utilize 1st and 3rd gears while in "D", and will use 2nd while in "2" or "L". All transmission operation in this mode will be at a preset line pressure (open loop). The transmission will resume normal operation (recover) if the detected problem goes away. Three recoveries are permitted in a given key, after the fourth occurrence the operation described above will be maintained.

Once the DRBIII® is in the "EATX" portion of the diagnostic program, it constantly monitors the TCM to see if the system is in limp-in mode. If the transmission is in limp-in mode, the DRBIII® will flash the red LED.

TRANSMISSION OPERATION AND SHIFT SCHEDULING AT VARIOUS OIL TEMPERATURES

The transmission covered in this manual has unique shift schedules depending on the temperature of the transmission oil. The shift schedule is modified to extend the life of the transmission while operating under extreme conditions.

The oil temperature is measured with a Temperature Sensor on the 45RFE/545RFE transmission.

The Temperature Sensor is an integral component of the Transmission Range Sensor (TRS). If the Temperature Sensor is faulty, (DTC P-1799) the transmission will default to a "calculated" oil temperature. Oil temperature will then be calculated using engine coolant temperature, battery/ambient temperature, and engine off time from the Body Control Module (BCM). These inputs are received from the communication bus periodically and are used to initialize the oil temperature at start up. Once the engine is started, the TCM updates the transmission oil temperature based on torque converter slip speed, vehicle speed, gear, and engine coolant temperature to determine an estimated oil temperature during vehicle operation. Vehicles using "calculated oil temperature" track oil temperature reasonably accurately during normal operation. However, if a transmission is overfilled, a transmission oil cooler becomes restricted, or if a customer drives aggressively in low gear, the calculated oil temperature will be inaccurate. Consequently the shift schedule selected may be inappropriate for the current conditions. The key highlights of the various shift schedules are as follows

Extreme Cold: Oil temperature below -27° C (-16° F)

Goes to "Super Cold" schedule when temp rises above -24 C (-12°F) oil temperature

Park, Reverse, Neutral and 1st and 3rd gear only

No Torque Converter Clutch engagement

Super Cold: Oil temperature between -27° C (-16° F) and -17° C (0° F)

Goes to "Cold" schedule above -12° C (10°F) oil temperature

Delayed 2-3 upshift

Delayed 3-4 upshift

Early 4-3 coastdown shift

Early 3-2 coastdown shift

No 3-1 coastdown or kickdown

High speed 4-2, 3-2, 2-1 kickdown shifts are prevented

No Torque Converter Clutch engagement

Cold: Oil temperature between -17° C (0° F) and 2° C (36° F)

Goes to "Warm" schedule when temp rises above 4.4 ° C (40°F) oil temperature

Shifts at higher throttle openings will be early

High speed 4-2, 3-2, 2-1 kickdown shifts are prevented

Delayed 3-4 upshift

Early 4-3 coastdown shift

Torque Converter Clutch engagement allowed with sump temp greater than 18° C (65° F)

Warm: Oil temperature between 2° C (36° F) and 27° C (80° F)

Normal operation (upshifts, kickdowns, and coastdowns)

No Torque Converter Clutch engagement allowed until sump temp above 18° C (65° F)

Hot (Normal operation): Oil temperature between 27° C (80° F) and 115° C (240° F)

Goes to "Overheat" schedule above 115° C (240°F) oil temperature

Reverts to "Hot" when temp falls below 110° C (230 ° F)

Normal operation (upshifts, kickdowns, and coastdowns)

Normal Torque Converter Clutch engagement operation

Overheat: Oil temperature above 115° C (240° F) or engine coolant temperature above 118° C (244° F)

Reverts to "Hot" when temp falls below 110° C (230°F) oil temp

Delayed 2-3 upshift 40-51 km/h (25-32 MPH)

Delayed 3-4 upshift 66-77 km/h (41-48 MPH)

3rd gear FEMCC from 48-77 km/h (30-48 MPH)

3rd gear PEMCC from 43-50 km/h (27-31 MPH)

A DTC P0218 High Temperature Operation Activated will be set in the TCM.

Causes for operation in the wrong temperature shift schedule

Extreme Cold or Cold shift schedule at start up

Temperature Sensor or circuitry.

Overheat shift schedule after extended operation

Operation in city traffic or stop and go traffic

Engine idle speed too high - Stuck AIS motor

Aggressive driving in low gear

Long idle time in drive position

Trailer towing in OD gear position (use "3" position if frequent shifting occurs)

Cooling system failure causing engine to operate over 110° C (230°F)

Engine coolant temperature stays low too long - If engine coolant temperature drops below 66° C (150°F), the transmission will disengage EMCC. Extended operation with the EMCC disengaged will cause the transmission to overheat.

Brake switch or circuitry - The TCM disengages the TCC when it receives a signal from the PCM that the brake has been depressed. A problem with the brake switch or circuitry will cause the EMCC to disengage. Extended operation with the EMCC disengaged will cause the transmission to overheat.

Transmission fluid overfilled

Transmission cooler or cooler lines restricted

Engine cooling fan inoperative

Temperature Sensor or circuitry.

DTC DESCRIPTIONS

Name of code: P0604. P0605. P0613 (ll. 13. 16, 17 or 45) - Internal Controller

When monitored: Whenever the key is in the Run or Run/Start position.

Set condition: This code is set whenever Transmission Control Module (TCM) senses an internal error

Theory of operation: The TCM is constantly monitoring its internal processor. If an internal problem is detected, this DTC will be set. This DTC can also be set by a bad ground to the TCM and/or Trans Control Relay. In fact, this DTC is rarely set due to a TCM error, it is usually set by a poor ground.

Transmission Effects: The MIL will illuminate (this DTC can take up to five minutes of problem identification before illuminating the MIL) and the transmission system will default to the Immediate Shutdown routine.

Possible causes

1. TCM ground circuit, (check main ground attachment to engine block)
2. Relay ground circuit, (check main ground attachment to engine block)
3. TCM

Name of code: P1684(12) - Battery was Disconnected (Info Only)

When monitored: Whenever the key is in the Run or Run/Start position.

Set condition: This code is set whenever Transmission Control Module (TCM) is disconnected from battery power (B+) or ground. It will also be set during the DRBIII® Quick Battery Disconnect procedure.

Theory of operation: A battery backed RAM (Random Access Memory) is used to maintain some learned values. When the battery B(+) is disconnected, the memory is lost. When the B(+) is restored, this memory loss is detected by the TCM. The code is set and the learned values are initialized to known constants or previously learned values from EEPROM (Electronic Erasable Programmable Read Only Memory). This results in the reinitialization of some parameters.

Transmission Effects: Loss of trouble code data. The Transmission system will default to the Immediate shutdown routine if power is lost while operating the vehicle. Normal operation is resumed if the power is restored during the same key start.

Possible causes

1. Battery voltage removed from TCM (Fused B+)
2. TCM disconnected
3. Dead Battery
4. Low battery voltage during cranking
5. Quick Battery Disconnect by DRBIII® or MDS
6. Bad TCM ground circuit.

Name of code: P0891(14) - Relay Always On

When monitored: When ignition key is turned from "off' position to "run" position and/or ignition key is turned from "crank" position to "run" position.

Set condition: This code is set if the Transmission Control Module (TCM) senses greater than 3 volts at the Trans Control Relay Output terminal(s) of the TCM prior to the TCM energizing the relay.

Theory of operation: The transmission control relay is used to supply power to the solenoids and pressure switches when the transmission is in normal operating mode. The relay output is fed back to the TCM through pins 16, 17, and 36. It is referred to as "Transmission Control Relay Output". This circuit does not supply power to the TCM, it is only a sense circuit. When the relay is off, no power is supplied to the solenoids and pressure switches, and the transmission is in "limp-in" or "default" mode.

Transmission Effects: The MIL will illuminate (this DTC can take up to five minutes of problem identification before illuminating the MIL) and the transmission system will default to the Immediate Shutdown routine.

Possible causes

1. Short to voltage in the Transmission Solenoid/ TRS Assembly (internal into any solenoid control circuit)
2. Short to voltage on any solenoid control circuit
3. Relay contacts stuck together.
4. Short to voltage in Transmission Control Relay output circuit(s).
5. Short to voltage in Transmission Relay Control circuit.
6. Short to voltage on any pressure switch sense circuit.
7. TCM connector problems.
8. TCM.

Name of code: P0888(15) - Relay Output Always Off

When monitored: Continuously

Set condition: This code is set when less than 3 volts are present at any transmission control relay output (pins 16,17 or 36) circuits at the Transmission Control Module (TCM) when the TCM is energizing the relay.

Theory of operation: The Transmission Control Relay is used to supply power to the solenoids and pressure switches when the transmission is in normal operating mode. The relay output is fed back to the TCM through pins 16, 17, and 36. It is referred to as "Transmission Control Relay Output". This circuit does not supply power to the TCM, it is only a sense circuit. When the relay is off, no power is supplied to the solenoids and pressure switches, and the transmission is in "limp-in" or "default" mode.

After a controller reset (ignition key turned to the "run" position or after cranking engine), the controller energizes the relay. Prior to this the TCM verifies that the contacts are open by checking for no voltage at the switched battery terminals. After the relay is energized, the TCM monitors the terminals to verify that the voltage is greater than 3 volts.

Transmission Effects: The MIL will illuminate (this DTC can take up to five minutes of problem identification before illuminating the MIL) and the transmission system will default to the Immediate Shutdown routine.

Possible causes

1. Transmission Control Relay (intermittent relay function caused by oxidized or contaminated relay contacts)
2. Short to ground or open circuit in the transmission control relay output circuit(s)
3. Short to ground or open circuit in the Transmission Solenoid/TRS assembly
4. TCM connector problem
5. Relay connector problem
6. Relay Ground circuit
7. TCM Ground circuit(s)
8. TCM

Name of code: P0725(18) - Engine Speed Sensor Circuit

Note. This code is not a Transmission Input Speed Sensor DTC

When monitored: Continuously with engine running.

Set condition: This code is set when the engine speed calculated by the Transmission Control Module (TCM) is less than 390 RPM, while the engine speed broadcast by the PCM is greater than 383 RPM. The DTC also sets if the calculated engine speed is greater than 8000 RPM for more that 2.0 seconds.

Theory of operation: The TCM uses the crank sensor signal to calculate engine RPM. The TCM uses RPM data from the PCM, which is broadcast over the communication bus to determine if the engine is running. The TCM continuously compares calculated engine speed to the engine RPM reported on the bus, by the PCM, so that loss of crankshaft position sensor signal to the TCM will not be misinterpreted as engine not running.

Transmission Effects: The MIL will illuminate (this DTC can take up to five minutes of problem identification before illuminating the MIL) and the transmission system will default to the Logical Shutdown routine.

Possible causes

1. Open or short in engine speed sensor circuit. (Crank sensor signal)
2. TCM connector problems (Crank sensor signal or sensor ground terminals)
3. Open or short in sensor ground circuit
4. Low engine idle speed
5. TCM
6. PCM.

Name of code: P1694(19) - Bus Communication with Engine Module

When monitored: Continuously with key on.

Set condition: If no bus messages are received from the Powertrain Control Module (PCM) for 10 seconds.

Theory of operation: The TCM communicates with the PCM using the communication bus. It relies on certain information to function properly. The TCM continuously monitors the bus to check for messages broadcast from the PCM.

Transmission Effects: Delayed 3-4 shifts. No EMCC and early 3-4 shifts for a few minutes after engine is started. Generally poor shift quality.

Possible causes

1. Open or shorted bus circuit
2. TCM
3. PCM

Name of code: P0706(28) - Check Shifter Signal

When Monitored: Continuously with the key on. Set Condition: Any occurrences of an invalid PRNDL code which lasts for more than 0.028 second.

Theory of Operation: The C1 through C5 (TRS T1, TRS T2, TRS T3, TRS T41, and TRS T42) sense circuits communicate the shift lever position to the TCM. Each circuit is terminated at the transmission with a switch. Each switch can be either open or closed, depending on the shift lever position. The TCM can decode this information and determine the shift lever position. Each shift lever position has it own unique combination of closed and open switches. This is called a PRNDL code. There are 5 switches, therefore: there are many possible combinations of open and closed switches (codes). There are 12 valid codes, two for neutral, one for each other gear position (5), and five temporary (transition zone) codes. The remainder of the codes should never occur, these are called invalid codes.

45RFE/545RFE TRS SWITCH STATES

DRBIII® REPORTED SHIFT LEVER ERROR CODES POSITION REFERENCE

Note. If you are using the transmission simulator and do not push the OD off button in the vehicle when performing a Shift Lever position test, you will receive a code 11 OD lockout stuck open

Transmission Effects and possible causes: (This code alone will not illuminate the MIL)

1. Excessive metal debris in the transmission oil pan
2. Worn Code Plate. Check for heavy wearing by TRS switch contacts
3. Intermittent C1 through C5 (T1, T2, T3, T41 or T42) circuits. Check for corrosion, terminal push-outs or spread terminals at TCM connector and/or 23-way transmission connector.
4. TRS connector not plugged in, or unplugged with the key on.
5. TRS C1 through C5 (T1, T2, T3, T41, or T42) circuit(s) are open, shorted to ground, or shorted to 12 volts.
6. TRS
7. TCM

Name of code: P0124(29) - Throttle Position Sensor /APPS Intermittent

Name of code: P0122(2A) - Throttle Position Sensor /APPS Low

Name of code: P0123(2B) - Throttle Position Sensor /APPS High

When monitored: Whenever the key is on or the engine is running. Engine speed > 500 rpm

Set condition: EATX

P0124 - Throttle angle change > 5° in 7 milliseconds the Fault set time milliseconds 0.448 seconds

P0122 - Throttle angle < 6° the Fault Set Time: 0.448 seconds

P0123 - Throttle angle > 120.6° the Fault Set Time: 0.448 seconds

Set condition: NGCII with Electronic Throttle Control

P0122 - is set if the pedal position sensor voltage falls below (.4v Diesel /.5v Gas).

P0123 - is set if the pedal position sensor voltage rises above (4.8v Diesel / 4.8v Gas).

P0124 - is set if the change in pedal position sensor voltage falls outside the limits

Theory of operation: EATX -The transmission controller receives the throttle position signal and its ground from the Throttle Position Sensor (TPS). The TPS has a 5 volt pull up supplied by the engine controller. The throttle signal is checked for out-of-range as well as intermittent operation (excessive signal changes). The engine controller transmits the throttle value via the bus. Most engine controllers can synthesize the throttle value if the throttle position sensor signal is lost. If a throttle error is detected by the transmission controller and the throttle value is available via the bus, the bus throttle value will be used and normal operation will continue, however a throttle fault code will be set. If a throttle error is detected and the throttle value is not available via the bus, normal operation will be discontinued, a throttle DTC will be set, and the MIL will be turned on after 5 min. of substituted operation.

Theory of operation: NGCII with Electronic Throttle Control 5.7L engines are equipped with a NGCII control module, which controls the Throttle Plate Position, based on torque management (request). This system has a throttle cable that is attached to two Accelerator Position Sensors instead of the throttle body. The throttle plate will not move with the ignition on while pressing the Accelerator Pedal. The only way to move the throttle plate with the ignition on is by using the DRBIII. The ETC Motor Assembly contains two Throttle Position Sensors, two springs, and the ETC Motor, which are replaced as a complete assembly. The TP Sensors inform the PCM of the position of the throttle plate. The ETC Motor has a positive and negative circuit. The PCM controls these circuits using Pulse Width Modulation. To open the throttle plate the PCM provides pulse width voltage to the positive side of the ETC motor and grounds the negative side. To close the throttle plate the PCM provides pulse width voltage to the negative side of the ETC motor and grounds the positive side. One of the springs is used against opening the throttle plate and the other is used against closing the throttle plate. The PCM uses the APP Sensor inputs along with inputs from the other Sensors to determine throttle opening. Duplicate sensors are used to check one sensor against its counterpart. Two TP Sensor, two, APP Sensors, two Brake Switch inputs, and two Speed Control inputs are used with the NGCII system. When duplicate Sensors are not used, the single Sensor is checked against a value that is calculated by the PCM. When a sensor fails, the PCM limits the opening of the Throttle blade. The customer may complain limited power and throttle control after the MIL and or ETC light illuminate. The ETC Light will constantly illuminate or flash depending on which component has failed. The ETC Motor Assembly will be referred to as Throttle Body Assembly in the Diagnostic and Service information. A slight delay in cranking may be noticed when starting the engine. When starting the vehicle the ETC Motor is tested before the engine is allowed to crank. The test includes opening and closing the throttle plate to verify proper operation before starting the engine for safety reasons. A No Crank Condition may occur if the Ignition in left in the on position for a period of time before actually cranking the engine. The PCM will test the throttle plate as often as it wants and will not allow cranking during this procedure. The throttle signal is checked for out-of-range as well as intermittent operation (excessive signal changes). The engine controller transmits the throttle value via the bus. Most engine controllers can synthesize the throttle value if the throttle position sensor signal is lost. If a throttle error is detected by the transmission controller and the throttle value is available via the bus, the bus throttle value will be used and normal operation will continue, however a throttle fault code will be set. If a throttle error is detected and the throttle value is not available via the bus, normal operation will be discontinued, a throttle DTC will be set, and the MIL will be turned on after 5 min. of substituted operation.

Transmission Effects

* If throttle value available via the bus -No effect.

* If throttle value not available via the bus, a default throttle value is used, Torque converter lock-up inhibited, 4th gear is inhibited, Limited transmission shift schedule, MIL on after 5 min. of substituted operation.

Possible causes

1. Wiring problem in APPS or TPS circuits
2. APPS
3. TPS
4. Throttle body
5. PCM
6. TCM

Name of code: P0944(35) - Loss Of Prime

When monitored: If the transmission is slipping in any forward gear and all the pressure switches are indicating no pressure, a loss of prime test is run.

Set condition: If the transmission begins to slip in any forward gear, and all pressure switches are open, a loss of prime test begins. All available elements are momentarily turned on by the Transmission Control Module (TCM) to see if pump prime exists. The code is set if none of the pressure switches respond. The TCM will continue to run the loss of prime test until pump pressure returns. Note: Loss of Prime test is not run when transmission temperature is "Super Cold".

Theory of operation: The loss of prime test is used to prevent transmission defaults, which can be caused by a lack of pump prime.

Transmission Effects: Vehicle will not move or transmission slips. Normal operation will continue if pump prime returns.

Possible causes

1. Low transmission fluid level
2. Transmission fluid filter improperly installed (Seal installed onto filter neck instead of into pump bore, seal not fully seated against pump bore housing, filter neck not engaged into pump, bolts loose or O-ring missing or damaged)
3. Transmission fluid filter clogged, damaged or cracked
4. Transmission has massive hydraulic leak (valve body pipe plugs missing, etc.)
5. Transmission oil pump
6. Transmission oil pump drive is sheared or damaged
7. PRNDL indicates a valid OD code in the hydraulic reverse position

Name of code: P1790(36) - Fault Immediately After Shift

When monitored: When a speed ratio error DTC (50 through 55) is stored.

Set condition: This code is set if the associated speed ratio code is stored within 1.3 seconds after a shift.

Theory of operation: This code will only be stored along with a 50 series code. If this code is set, it indicates a probable hydraulic (line pressure) or mechanical problem exists. When this code is set, diagnosing the transmission should be based on the associated speed ratio code and mechanical causes should be considered first.

Transmission Effects: None Possible causes

1. Mechanical causes as listed under associated speed ratio code.
2. Inadequate line pressure
3. Cut or damaged clutch piston seals

Name of code: P1775(37) - Solenoid Switch Valve Latched in TCC Position

When monitored: During an attempted shift into 1st gear.

Set condition: This code is set if 6 unsuccessful attempts are made to get into 1st gear, with transmission temp above 27° C (80° F), in one given key start.

Theory of operation: The solenoid switch valve (SSV) controls the direction of the transmission fluid when the L-R solenoid is energized. The SSV will be in the downshifted position in 1st gear, thus directing the fluid to the L-R clutch circuit. In 2nd, 3rd, and 4th, it will be in the upshifted position and directs the fluid into the torque converter clutch (TCC).

When shifting into 1st gear, a special hydraulic sequence is performed to ensure SSV movement into the downshifted position. The L-R pressure switch is monitored to confirm SSV movement. If movement is not confirmed (the L-R pressure switch does not close), EMCC is inhibited until SSV operation is confirmed.

Transmission Effects: Transmission will have 1st gear and no EMCC operation. The MIL will illuminate after 5 minutes of no EMCC operation.

Possible causes

1. Valve body - Solenoid Switch Valve stuck in TCC position
2. L-R solenoid armature or plunger broken - should also set DTC P0841 (81) and often sets P0740 (38)
3. Solenoid malfunction - may also set code P0841 (81)
4. L-R Pressure Switch Sense circuit shorted to battery
5. High idle speed
6. PRNDL indicates a valid OD code in the hydraulic reverse position

Name of code: P0740(38) - Torque Converter Clutch Control Circuit

When monitored: During Electronically Modulated Converter Clutch (EMCC) Operation

Set condition: The code will be set if one of the following events happens three times in a given key start, at a throttle angle less than 30(

1. With the transmission in EMCC, the TCC/L-R solenoid achieves the maximum duty cycle and is still unable to pull the engine speed within 60 RPM of input speed.
2. With the transmission in FEMCC, the TCC RPM (Engine speed - Input speed) is more than 100 RPM for 7.2 seconds.

Theory of operation: When in 2nd, 2nd Prime, 3rd, or 4th gear, the torque converter clutch (TCC) can be engaged when certain conditions are met. The TCC piston is electronically modulated by increasing the duty cycle of the L-R solenoid until the torque converter slip difference (difference between engine and transmission input speed) is within 60 RPM. Then the L-R solenoid is fully energized (FEMCC /100% duty cycle). Torque converter slip is monitored in FEMCC to ensure adequate clutch capacity.

Transmission Effects: EMCC will still be available after code is set. MIL will illuminate after 5 minutes of accumulated slip in FEMCC. The transmission will attempt normal operation (no limp-in) even after the MIL is illuminated.

Possible causes

1. Cut converter hub O-ring and/or failed torque converter - both should be replaced during a rebuild with code P0740(38) present.
2. Sticky CC Regulator valve

Name of code: P1776(47) - Solenoid Switch Valve (SSV) Latched in L-R Position

When monitored: Continuously when doing partial or full EMCC (PEMCC or FEMCC)

Set condition: If the transmission senses the L-R pressure switch closing while performing PEMCC or FEMCC. This code will be set after four unsuccessful attempts to perform PEMCC or FEMCC.

Theory of operation: The solenoid switch valve (SSV) controls the direction of the transmission fluid when the L-R solenoid is energized. SSV will be in the downshifted position in 1st gear, thus directing the fluid to the L-R clutch circuits. In 2nd, 3rd, and 4th, the SSV will be in the upshifted position and directs the fluid into the torque converter clutch (TCC). When doing PEMCC or FEMCC, the L-R pressure switch should indicate no pressure if the SSV is in the TCC position. If the L-R pressure switch indicates pressure while in PEMCC or FEMCC, EMCC operation is aborted and inhibited to avoid inadvertent application of the L-R clutch. Partial EMCC will be attempted if the L-R pressure switch does not indicate pressure. Four occurrences of detection of L-R pressure results in setting the code.

Transmission Effects: EMCC is inhibited and the transmission system will default to the Orderly Shutdown routine, (this DTC can take up to five minutes of problem identification before illuminating the MIL)

Possible causes

1. Valve body - Solenoid Switch Valve stuck in L-R position
2. Intermittent short to ground or open circuit in L-R Pressure Switch Sense circuit (with code P0841 only)
3. Solenoid/TRS assembly (with code P0841(81) only)
4. TCM (with code P0841(81) only)

Name of Code: P1793(48) - Torque Reduction (TRD) Link Communication Error

When Monitored: During torque managed shifts (Throttle angle above 54 degrees). This system is also tested whenever the vehicle is stopped and the engine speed is below 1000 RPM.

Set condition: This code is set when the Transmission Control Module (TCM) sends two subsequent torque reduction messages to the Powertrain Control Module (PCM) via the TRD link circuit and does not receive a confirmation from the PCM over the communication bus.

Theory of Operation: During high torque shifts the TCM will send a message requesting that the PCM reduce engine power until the shift is completed. This message is sent from the TCM to the PCM across the Torque Management Request Sense Circuit. The PCM will acknowledge the TCM request by sending a confirmation message across the communication bus. The TRD Link communication is also tested periodically for operation whenever the engine is running and the vehicle is not moving with zero degrees throttle.

Transmission Effects: Maximum throttle angle used by TCM will be 54 degrees. As a result a customer may complain about loss of performance and/or normal and WOT shifts may be harsh.

Possible Causes

Sticky Throttle Position Sensor (TPS)

1. Wiring or Connector problems in the Torque Management Request Sense Circuit
2. Bus communication problems.
3. PCM
4. TCM

Name of code

P0736(50) - Gear Ratio Error in Reverse

P0731(51) - Gear Ratio Error in 1st

P0732(52)- Gear Ratio Error in 2nd

PQ733(53) - Gear Ratio Error in 3rd

P0734(54) - Gear Ratio Error in 4th

P1736(55) - Gear Ratio Error in 2nd Prime

P0715(56) - Input Speed Sensor

P0720(57) - Output Speed Sensor

P1794(58) - Speed Sensor Ground

P0735(59) - Gear Ratio Error in 4th Prime

When monitored: The transmission gear ratio is monitored continuously while the transmission is in gear.

Set condition: This code is set if the gear ratio is not correct for the current gear.

1. Codes 50 through 59 sets if the ratio of the input RPM (Nt) to the output RPM (No) does not match the current gear ratio.
2. Code 56 sets if there is an excessive change in input RPM in any gear
3. Code 57 sets if there is an excessive change in output RPM in any gear
4. Code 58 sets after a TCM reset in neutral and Nt/No equals a ratio of input to output of 2.00

Theory of operation: The transmission system uses two speed sensors, one to measure input RPM and one to measure output RPM. These inputs are essential for proper transmission operation. Therefore, the integrity of this data is verified through the following checks

1. When in gear, if the gear ratio does not compare to a known gear ratio, the corresponding in-gear trouble code is set (codes 50 through 59).
2. An excessive change in input or output speeds indicating signal intermittent will result in codes 56 and/or 57 being set.
3. If the common speed sensor ground circuit is lost, both sensor inputs will read the signal from the input speed sensor at idle in neutral. Since the input speed sensor has 60 teeth and the output speed sensor has 30 teeth, this results in a ratio of 2.00.

Transmission Effects: If a gear ratio error develops, the appropriate code is set as a one trip failure and the 5 minute Intelligent Recovery Timer (IRT) is started. The transmission will then substitute a 1-3 or 3-1 shift to a different gear for the one in which the problem was identified. For example, if a problem is identified while in first gear, the transmission will shift to third gear. The IRT is only counting up while the transmission is substituting one gear for another. Using the previous example, if the vehicle continued down the road and shifted to fourth gear for a long period of time, the IRT would have only counted the time that the transmission was in third gear instead of second. The MIL will illuminate (this DTC can take up to five minutes of problem identification before illuminating the MIL). The transmission system will default to the Logical Shutdown (without recovery) routine after 5 minutes of substituted gear operation or if three gear ratio error events occur in a given key start.

Possible causes

Code P0736(50) - Excludes gear train failures that should be obvious upon disassembly

1. If code P0944(35) or any line pressure DTC's are set, diagnose these first
2. Valve body - #3 check ball
3. L-R switch valve sticking - may also set code P0731(51)
4. Speed sensor or associated wiring - may also set codes P0731(51), P0715(56), or P0720(57)
5. Multi Select Solenoid sticking or leaking
6. Failed or slipping L-R clutch - may also set code P0731(51) L-R seal leakage (Intermittent no drive or reverse) Sticky L-R accumulator seals (Intermittent no drive or reverse)
7. Failed reverse clutch (hard code) OD/Rev lip seal leakage Worn reaction shaft support seal rings Code P0731(51) - Excludes gear train failures which should be obvious upon disassembly
8. If code P0944(35) or any line pressure DTC's are set, diagnose these first
9. Valve body - #1, #2, and/or #4 check ball
10. L-R switch valve sticking
11. Speed sensor or associated wiring - may also set codes P0736(50), P0715(56), or P0720(57)
12. Solenoid/TRS assembly (stuck solenoid(s))
13. Failed or intermittent slipping UD clutch - may also set P0732(52) or P0733(53) UD seal leakage Sticky UD accumulator seals Worn reaction shaft support seal rings
14. Failed or slipping L-R clutch - may have code P0736(50) L-R seal leakage Sticky L-R accumulator seals Code P0732(52) - Excludes gear train failures which should be obvious upon disassembly
15. If code P0944(35) or any line pressure DTC's are set, diagnose these first
16. Valve body - #1, #2, #4, #5 and/or #7 check ball
17. Solenoid/TRS assembly - may also set codes P0846(54) and/or P0845(A2)
18. Failed or slipping 2nd clutch 2nd clutch seal leakage Sticky 2nd clutch accumulator seals
19. Failed or intermittent slipping UD clutch - may also set code P0731(51) and/or P0733(53) UD clutch seal leakage Worn input hub bushing Sticky UD clutch accumulator seals Worn reaction shaft support seal rings Code P0733(53) - Excludes geartrain failures which should be obvious upon disassembly
20. If code P0944(35) or any line pressure DTC's are set, diagnose these first
21. Valve body - #1, #2, and/or #6 check ball
22. Speed sensor or associated wiring - may also set codes P0736(50), P0715(56), or P0720(57)
23. Solenoid/TRS assembly - may also set codes P087K84) and/or P0870(A4)
24. Failed or slipping OD clutch - may also set code P0734(54) OD clutch inner and outer lip seal leakage Sticky OD clutch accumulator seals Worn reaction shaft support seal rings
25. Failed or intermittent slipping UD clutch - may also set codes P0731(51) and/or P0732(52) UD seal leakage Worn input hub bushing Sticky UD clutch accumulator seals Worn reaction shaft support seal rings Code P0734(54) - Excludes gear train failures which should be obvious upon disassembly
26. If code P0944(35) or any line pressure DTC's are set, diagnose these first
27. Valve body - #1, #2, #5 and/or #6 check ball
28. Speed sensor or associated wiring - may also set codes P0736(50), P0715(56), or P0720(57)
29. Solenoid/TRS assembly - may also set codes P0988(88) and/or P0987(A8)
30. Failed or slipping OD clutch - may also set code P0733(53) OD clutch inner and outer lip seal leakage Sticky OD clutch accumulator seals Worn reaction shaft support seal rings
31. Failed or intermittent slipping 4th clutch 4th clutch seal leakage Sticky 4th clutch accumulator seals Worn reaction shaft support seal rings Code P1736(55) - Excludes gear train failures which should be obvious upon disassembly
32. If code P0944(35) or any line pressure DTC's are set, diagnose these first
33. Valve body - #1, #4 and/or #5 check ball
34. Speed sensor or associated wiring - may also set codes P0736(50), P0715(56), or P0720(57)
35. Solenoid/TRS assembly - may also set codes P0876(90) and/or P0875(BO)
36. Failed or intermittent slipping UD clutch - may also set codes P0731(51) and/or P0732(52) UD seal leakage Worn input hub bushing Sticky UD clutch accumulator seals Worn reaction shaft support seal rings
37. Failed or intermittent slipping 4th clutch 4th clutch seal leakage Sticky 4th clutch accumulator seals Worn reaction shaft support seal rings Codes P0715(56) and P0720(57)
38. Failed input or output speed sensor
39. Shorted or open wiring between TCM and speed sensor(s)
40. Connector problems at TCM connector and/or speed sensor connector(s)
41. Transmission Solenoid /TRS Assembly has an internal short to the Speed Sensor Ground circuit (should also set a P1794 and P0711). Code P1794(58)
42. Open or shorted speed sensor ground (speed sensor ground is different from chassis ground)
43. Open or shorted Temperature Sensor wiring to TRS
44. Transmission Solenoid /TRS Assembly has an internal short to the Speed Sensor Ground circuit
45. TRS - Will also set code P0713(7C)
46. TCM Code P0735(59) - Excludes gear train failures which should be obvious upon disassembly
47. If code P0944(35) or any line pressure DTC's are set, diagnose these first
48. These codes may also be set with the DTC - P1790(36), P0846(82), P087K84), P0845(A2), P0870(A4), perform these diagnostics first.
49. Speed sensor or associated wiring - may also set codes P0736C50), P0715(56), or P0720(57)
50. Solenoid/TRS assembly (stuck solenoid(s))
51. Failed or slipping OD clutch OD seal leakage
52. Failed or slipping 2C clutch 2C seal leakage

Name of Code: P2700. P2701. P2702, 2703. 2704 (60, 61, 62, 63, 64) - Inadequate Element Volume

When Monitored: Whenever the engine is running, the clutch volume is updated during the requested shift.

Set condition

Note. Transmission temperature must be 43° C (110° F) to update all volumes.

1. P2700 - When the LR volume falls below 16, the LR volume is updated during a 3-1 or 2-1 manual downshift with the TPS angle below 5 degrees.
2. P2701 - When the 2C volume falls below 5, the 2C volume is updated during a 3-2 kick-down with the TPS angle between 10 and 54 degrees.
3. P2702 - When the OD volume falls below 6, the OD volume is updated during a 2-3 upshift with the TPS angle between 10 and 54 degrees.
4. P2703 - When the UD volume falls below 11, the UD volume is updated during a 4-3 kick-down with the TPS angle between 30 and 54 degrees.
5. P2704 - When the 4C volume falls below 30, the 4C clutch volume is updated when doing a 3-4 shift with throttle angle between 10° and 54°. The transmission temperature must be above 43 C (110°F). The clutch volume should be between 30 and 85.

Theory of Operation: The volumes of the transmission fluid needed to apply the friction elements are continuously monitored and learned for adaptive controls. As the clutch friction material wears, the volume of fluid needed to apply the clutch increases. The following are typical clutch volumes, the clutches may be damaged if the volumes are greater or less than the specified below

2C clutch volume - between 25 and 85

OD clutch volume - between 30 and 100

4C clutch volume - between 30 and 85

UD clutch volume - between 30 and 100

Transmission Effects: These codes usually set with other DTC's, which indicates an internal transmission problem.

Possible Causes

1. Clutch pack clearance out of spec
2. Snap ring out of position or broken
3. Broken return spring
4. Hydraulic leak into clutch circuit with near-zero volume

Name of Code: P1715(65) - Restricted Port in T3 Range

When Monitored: Whenever the Engine is running and the Manual valve is in the T3 range.

Set condition: The code is set if the conditions for a code 47 are present when the manual valve is in the T3 range.

Theory of Operation: The conditions to set a DTC 47 are easily satisfied while in the T3 range. There is no problem with the transmission itself if this code is set.

Transmission Effects: The transmission will go into neutral when this code is set. If the driver puts the shifter in neutral and back to drive, the transmission will operate normally.

Possible Causes

1. Manual linkage out of adjustment, causing T3 range while shifter is in OD.
2. Driver resting hand on shift lever while driving, causing T3 range.

Name of Code: P0218(75) - High Temperature Operation Activated

When Monitored: Whenever the engine is running.

Set Condition: Immediately when the Overheat shift schedule is activated.

Theory of Operation: If the transmission oil temperature rises above 116° C (240° F), the overheat shift schedule is activated, refer to the Transmission Operation as a function of Transmission Oil Temperature. The code is an information code only and is being set to aid the technician in determining root cause of a customer driveability issue. The code is also intended to alert the technician to determine if a cooling system malfunction has occurred or if an additional transmission air to oil cooler should be added to the vehicle if the customer regularly drives in a manner that overheats the transmission. Extended operation above 116° C (240° F) will reduce the durability of the transmission and should be avoided. Correcting the cooling system malfunction or installing an additional transmission oil cooler will improve transmission durability especially for customers who operate in city/construction stop and go traffic, tow trailers regularly, drive aggressively in low gear or drive regularly in mountainous areas.

Transmission Effects: Information only code. -Overheat shift schedule was activated, no limp-in condition occurs. See description of overheat shift schedule.

Possible Causes

1. Transmission Overfilled with Oil
2. Engine cooling fan failure
3. Engine thermostat stuck closed
4. Radiator corroded or packed with dirt
5. Transmission cooler corroded or packed with dirt
6. Transmission fan not functioning properly
7. Transmission Oil Cooler Plugged
8. Customer driving pattern requires additional transmission cooling

Name Of Code: P0884(76) - Power-Up at Speed

When Monitored: When TCM (Transmission Control Module) initially powers-up.

Set Condition: If the TCM powers up and senses a valid forward gear PRNDL code and the output RPM is above 800 RPM approx. 32 km/h (20 MPH) the code will be set.

Theory of Operation: If a vehicle loses power to the TCM, the solenoids will go to their respective power off state. Some solenoids are normally vented and some are normally applied in their power off state. The transmission is designed to be in 3rd gear with all of the solenoids in this state. However, if power is restored, the TCM will power-up and normal operation will be restored. This code identifies that power to the TCM was restored when the gear selector was in a "Drive" position while the vehicle was moving at speeds above 32 km/h (20 MPH). This code does not indicate a problem with the transmission or TCM, instead, it suggests intermittent problems in the fused ignition switch output, fused B(+), or ground circuits to the TCM. Alternately, if a person performs a rolling restart maneuver, the code can be set. Therefore it is critical that this DTC be investigated if the vehicle is experiencing intermittent 3rd gear operation and a subsequent return to normal operation.

Transmission Effects: No limp-in, although the symptom might be described as an intermittent limp-in. Code is for information only when trying to diagnosis intermittent 3rd gear operation and a subsequent return to normal operation.

Possible Causes

1. No Problem if vehicle is started in "neutral" at speeds above 32 km/h (20 MPH) and shifted quickly to a forward gear position.
2. Quick key off then on while driving is any forward gear.

FOR INTERMITTENT 3rd GEAR OPERATION AND THEN A SUBSEQUENT RETURN TO NORMAL OPERATION WITHOUT CYCLING THE IGNITION KEY

1. Intermittent Direct Battery (Fused B(+)) connection between TCM (60-way pin 56) and battery.
2. Intermittent Fused Ignition Switch Output between TCM (60-way pin 11) and ignition switch.
3. Intermittent Ground to TCM (60 way pins 53 and 57).

Name of Code: P0711(7A) - Transmission temperature sensor performance

When Monitored: Every 7 milliseconds with the engine running and no loss of prime DTC set.

Set condition: A temperature reading of 80° F is not reached in the specified period of time

Theory of Operation: The temperature sensor (thermistor) is used to sense the temperature of the transmission fluid. Transmission fluid temperature can affect shift quality, torque converter lock-up, and when and if some diagnostics are run. A failed temperature sensor could affect the OBD II diagnostics, therefore when a fault is detected in the temperature sensor circuit, transmission temperature will be based on a calculated temperature value.

Transmission Effects: When the fault is set, calculated temperature is substituted for measured temperature, however the DTC is stored only after three consecutive occurrences of the fault.

Possible Causes

1. Temperature sensor
2. Temperature sensor wiring circuit.
3. TCM

Name of Code: P0712(7B) - Transmission temperature sensor low

When Monitored: Every 7 milliseconds with the engine running and no loss of prime DTC set.

Set condition: Sensor output voltage less than 0.078v.

Theory of Operation: The temperature sensor (thermistor) is used to sense the temperature of the transmission fluid. Transmission fluid temperature can affect shift quality, torque converter lock-up, and when and if some diagnostics are run. A failed temperature sensor could affect the OBD II diagnostics, therefore when a fault is detected in the temperature sensor circuit, transmission temperature will be based on a calculated temperature value.

Transmission Effects: When the fault is set, calculated temperature is substituted for measured temperature, however the DTC is stored only after three consecutive occurrences of the fault.

Possible Causes

1. Temperature sensor
2. Temperature sensor wiring circuit.
3. TCM

Name of Code: P0713(7C) - Transmission temperature sensor high

When Monitored: Every 7 milliseconds with the engine running and no loss of prime DTC set.

Set condition: Sensor output voltage greater than 4.94v.

Theory of Operation: The temperature sensor (thermistor) is used to sense the temperature of the transmission fluid. Transmission fluid temperature can affect shift quality, torque converter lock-up, and when and if some diagnostics are run. A failed temperature sensor could affect the OBD II diagnostics, therefore when a fault is detected in the temperature sensor circuit, transmission temperature will be based on a calculated temperature value.

Transmission Effects: When the fault is set, calculated temperature is substituted for measured temperature, however the DTC is stored only after three consecutive occurrences of the fault.

Possible Causes

1. Temperature sensor
2. Temperature sensor wiring circuit.
3. TCM

Name of Code: P0714(7D) - Transmission temperature sensor intermittent

When Monitored: Every 7 milliseconds with the engine running and no loss of prime DTC set.

Set condition: Temperature reading changes are greater than maximum change allowed.

Theory of Operation: The temperature sensor (thermistor) is used to sense the temperature of the transmission fluid. Transmission fluid temperature can affect shift quality, torque converter lock-up, and when and if some diagnostics are run. A failed temperature sensor could affect the OBD II diagnostics, therefore when a fault is detected in the temperature sensor circuit, transmission temperature will be based on a calculated temperature value.

Transmission Effects: When the fault is set, calculated temperature is substituted for measured temperature, however the DTC is stored only after three consecutive occurrences of the fault.

Possible Causes

1. Temperature sensor
2. Temperature sensor wiring circuit.
3. TCM

Name of code: P0890(80) - Switched Battery

When monitored: Ignition key is turned from "off" position to "run" position and/or ignition key is turned from "crank" position to "run" position.

Set condition: This code is set if the Transmission Control Module (TCM) senses voltage on any of the pressure switch inputs prior to the TCM energizing the relay.

Theory of operation: The Transmission control relay is used to supply power to the solenoids and pressure switches when the transmission is in normal operating mode. When the relay is off, no power is supplied and the transmission is in "limp-in" mode. The relay output is fed back to the TCM through pins 16, 17 and 38. It is referred to as "Transmission Control Relay Output". Immediately after a controller reset (ignition key turned to the "run" position or after cranking engine), the TCM verifies that the relay contacts are open by checking for no voltage at the transmission control relay output terminals. After this is verified, the voltage at the pressure switches is checked. There should be no voltage on the pressure switches at this time. The TCM will then activate the relay.

Transmission Effects: The MIL will illuminate and the transmission system will default to the Immediate Shutdown routine.

Possible causes

1. Short to battery on one or more pressure switch sense circuits.
2. TCM connector problems.
3. Solenoid/TRS connector problems.
4. TCM.

Name of code

P0841(81) - LR Pressure Switch Sense Circuit

P0846(82) - 2C Pressure Switch Sense Circuit

P087K84) - OP Pressure Switch Sense Circuit

P0988(88) - 4C Pressure Switch Sense Circuit

P0876(90) - UP Pressure Switch Sense Circuit

When monitored: Whenever the engine is running.

Set condition: The appropriate code is set if one of the pressure switches are open or closed at the wrong time in a given gear (see chart below). Theory of operation: The Transmission system uses five pressure switches to monitor the fluid pressure in the LR, 2C, 4C, UD, and OD clutch circuits. The pressure switches are continuously monitored for the correct states in each gear as shown below.

45RFE/545RFE NORMAL PRESSURE SWITCH STATES

Note. L/R PRESSURE SWITCH OPENS ABOVE 150 OUTPUT RPM IN 1ST GEAR AND CLOSES BELOW 100 OUTPUT RPM.

Transmission Effects: The MIL will illuminate and the transmission system will default to the Immediate shutdown routine.

Possible causes

1. If code P0944(35) is present, perform code P0944(35) diagnostic procedures
2. Transmission fluid filter improperly installed (Seal installed onto filter neck instead of into pump bore, seal not fully seated against pump bore housing, filter neck not engaged into pump, bolts loose or O-ring missing or damaged)
3. Reverse carrier snap ring dislodged (typically sets on heavy throttle acceleration from a dead stop)
4. Pressure switch sense circuit open or shorted to ground between TCM and Solenoid/TRS assembly
5. Pressure switch sense circuit shorted to battery
6. Pressure switch
7. Loose valve body bolts
8. Plugged filter - internal transmission or torque converter failure
9. Check ball not seating or damaged.
10. Solenoid malfunction (If set with corresponding Solenoid DTC. le: 2C Pressure switch set with 2C solenoid)
11. Oil Pump (Code P0841(81) only)
12. TCM

Name of code

P0845(A2) - 2C Hydraulic Pressure test failure

P0870(A4) - OD Hydraulic Pressure test failure

P0987(A8) - 4C Hydraulic Pressure test failure

P0875(BO) - UD Hydraulic Pressure test failure

When monitored: In any forward gear with engine speed above 1000 RPM shortly after a shift and every minute thereafter.

Set condition: Immediately after a shift into a forward gear, with engine speed above 1000 RPM, the TCM momentarily turns on element pressure to the clutch circuits that do not have pressure to identify that the appropriate pressure switch closes. If the pressure switch does not close it is tested again. If the switch does not close the second time, the appropriate code is set.

Theory of operation: The Transmission Control Module (TCM) tests the pressure switches when they are off. The test verifies that the switches are operational (They will close with pressure applied). The TCM verifies that the switch closes when the corresponding element is applied. If a switch fails to close, it is re-tested. If it fails the second test, the code is set.

Transmission Effects: The MIL will illuminate and the transmission system will default to the orderly Shutdown routine

Possible causes

1. Line Pressure Sensor
2. Pressure switch sense circuit shorted to battery between TCM and solenoid/TRS assembly.
3. Solenoid malfunction (If set with corresponding Solenoid DTC. le: 2C Hydraulic Pressure switch set with 2C solenoid)
4. Low oil pressure
5. Pressure switch

Name of code

P0750(C1) - LR Solenoid Circuit

P0755(C2) - 2C Solenoid Circuit

P0760(C3) - QD Solenoid Circuit

P0770(C4) - 4C Solenoid Circuit

P0765(C5) - UD Solenoid Circuit

P2706(C6) - MS Solenoid Circuit

When monitored: Initially at power-up, then every 10 seconds thereafter. They will also be tested immediately after a gear ratio or pressure switch error is detected.

Set condition: Three consecutive solenoid continuity test failures, or one failure if test is run in response to a gear ratio or pressure switch error.

Theory of operation: Six solenoids are used to control the friction elements (clutches). The continuity of the solenoid circuits are periodically tested. Each inactive solenoid is turned on for a few milliseconds, then off. Each active solenoid is turned off for a few milliseconds, then on. This pulsing of voltage to the solenoid causes an inductive spike which can be sensed by the TCM. If an inductive spike is not sensed by the Transmission Control Module (TCM) during the continuity check, it is tested again. If the test fails three consecutive times, the appropriate code is set. If the solenoid test is run in response to a gear ratio or pressure switch error, one failure will result in setting the appropriate code.

Transmission Effects: The MIL will illuminate and the transmission system will default to the Immediate Shutdown routine.

Possible causes

1. Open or shorted solenoid circuit(s) between TCM and solenoid/TRS assembly.
2. Open ground circuit.
3. TCM connector problems.
4. Solenoid/TRS connector problem.
5. Solenoid/TRS assembly.
6. TCM

Name of code

P0868(C9) - Line Pressure Low

P0869(CB) - Line Pressure High

P0932(CA) - Line Pressure Sensor Circuit fault

P0934(CC) - Line Pressure Sensor Low

P0935(CD) - Line Pressure Sensor High

P0932 - When monitored: Continuously while driving in a forward gear.

Set condition: The TCM continuously monitors transducer Line Pressure Output and compares it to Desired Line Pressure. If the difference between transducer Line Pressure output and Desired Line Pressure is 10 PSI or greater, the DTC will set in approximately 3.57 seconds.

P0934- When monitored: Set condition: Continuously with engine running and Output Speed greater than 390 RPM.

Set condition: This DTC will set when the Line Pressure Sensor output is less than 0.35 volts for 1.4 seconds.

P0935- When monitored: Continuously with engine running, Output Speed greater than 390 RPM and Desired Line Pressure less than 200.

Set condition: This DTC will set if is Line Pressure Sensor Output is greater than 4.75 volts for 1.4 seconds.

P0868- When monitored: Continuously while driving in a forward gear.

Set condition: The TCM continuously monitors transducer Line Pressure Output and compares it to Desired Line Pressure. If transducer Line Pressure Output is more than 10 PSI below Desired Line Pressure, the DTC will set in approximately 2.1 seconds.

P0869- When monitored: Continuously while driving in a forward gear.

Set condition: The TCM continuously monitors transducer Line Pressure Output and compares it to Desired Line Pressure. If transducer Line Pressure Output is more than 10 PSI above Desired Line Pressure, the DTC will set in approximately 3.57 seconds.

Theory of operation: Line pressure is controlled by the TCM. It is measured by the Line Pressure Sensor (LPS) and regulation is achieved by changing the duty cycle of the Pressure Control Solenoid (PCS). (5% duty cycle = solenoid off = max line pressure, 62% duty cycle = solenoid on = min line pressure). The TCM calculates the desired line pressure based on inputs from the transmission and engine. The TCM calculates torque input to the transmission and uses it as the primary input to the desired line pressure calculation. This is called Torque Based Line Pressure. In addition, the line pressure is set to a preset level 827 or 931kPa (120 or 135 PSI) during shifts and in Park and Neutral to ensure consistent shift quality. The desired line pressure is continuously being compared to the actual line pressure. If the actual line pressure is consistently higher than the target, the line pressure high DTC P0869(CB) will be set. If the actual line pressure is consistently lower than the target, the line pressure low DTC P0868(C9) will be set. If it is consistently out of range, but not consistently high or low, it is considered out of range and the line pressure error DTC P0932(CA) will be set.

Transmission Effects: The Transmission system will default to open loop line pressure control resulting in a fixed PCS duty cycle. This duty cycle will change slightly depending on temperature and current gear.

Possible causes

1. Sticking Regulator Valve
2. Pressure Control Solenoid
3. Line Pressure Sensor.
4. Oil pump
5. Plugged Filter
6. 5V supply circuit to Line Pressure Sensor open (Sensor reading will display a constant value between 586 and 655 kPa (85 and 95 PSI)
7. LPS signal circuit shorted to ground, shorted to voltage, or open.
8. 5-volt supply circuit shorted to ground, shorted to voltage, or open.
9. Open sensor ground
10. TCM

Name of code: P2620(2C) - ETC Throttle Position Output Circuit

When monitored: Continuously with the ignition on.

Set condition: The Pulse Accumulator Input Counter (PAIC) is a hardwired frequency modulated signal that the TCM receives from the engine controller. When the frequency transmitted exceeds specified limits, the DTC will set.

Theory of operation: The TCM software tracks the frequency modulated signal with a counter called PAIC.

The PAIC is the hardwired frequency modulated signal received from the engine controller. The limits on the counter are: PAIC minimum value = 6, PAIC maximum value = 150. If the PAIC is within limits, the counter is decremented by (-1). If the PAIC is out of the limits we increment (+4) the FM out of Range counter. When the counter reaches 250, the TCM will set the ETC Throttle Position Output Circuit DTC.

Transmission Effects: No MIL light. The transmission will not be placed into limp-in mode. IF the TPS NO. 1 Output signal is not present the EATX software will acquire the throttle from the bus, use the or use the APPS No. 1 Output signal or a default value.

Possible causes

1. TPS NO. 1 Output circuit open, shorted to ground, voltage
2. TCM
3. PCM