Part 2
DTC P1779 (P0731): 1st Gear Incorrect RatioDTC P1780 (P0732): 2nd Gear Incorrect Ratio
DTC P1781 (P0733): 3rd Gear Incorrect Ratio
DTC P1782 (P0734): 4th Gear Incorrect Ratio
DTC P1783 (P0735): Ruth Gear Incorrect Ratio [5A/T]
DTC P1784 (P0736): Reverse Gear Incorrect Ratio
(continued)
DIAGNOSIS
Required Special Tool:
^ MB991958: Scan Tool (M.U.T-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: M.U.T-III USB Cable
^ MB991910: M.U.T-III Main Harness A
STEP 1. Using scan tool MB991958, read the A/T diagnostic trouble code.
CAUTION
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Check for A/T diagnostic trouble code.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC set?
YES [DTC P1766 set]: Refer to DTC P1766: Input Shaft Speed Sensor System. P1766
YES [DTC P1767 set]: Refer to DTC P1767: Output Shaft Speed Sensor System. P1767
YES [DTC P1773 set]: Refer to DTC P1773: Low-Reverse Solenoid Valve System. P1773
YES [DTC P1774 set]: Refer to DTC P1774: Underdrive Solenoid Valve System. P1774
YES [DTC P1775 set]: Refer to DTC P1775: Second Solenoid Valve System. P1775
YES [DTC P1776 set]: Refer to DTC P1776: Overdrive Solenoid Valve System. P1776
YES [DTC P1777 (P0773) set]: DTC P1777 (P0773): Reduction Solenoid Valve System [5A/T]. P1777
NO: Go to Step 2.
STEP 2. Check the hydraulic pressure.
Each hydraulic pressure of the elements below, which DTCs indicate, should be within the standard value.
^ DTC P1779 (P0731): Underdrive clutch, low-reverse brake and reduction brake [5A/T]
^ DTC P1780 (P0732): Underdrive clutch, second brake and reduction brake [5A/T]
^ DTC P1781 (P0733): Underdrive clutch, overdrive clutch and reduction brake [5A/T]
^ DTC P1782 (P0734): Overdrive clutch, underdrive clutch [5A/T] second brake [4A/T] and direct clutch [5A/T]
^ DTC P1783 (P0735) [5A/T]: Overdrive clutch, second brake and direct clutch
^ DTC P1784 (P0736): Reverse clutch and low-reverse brake
Q: Are the hydraulic pressures within the standard value range?
YES: Go to Step 5.
NO [out of the range in one place]: Go to Step 4.
NO [out of the range in all places]: Go to Step 3.
STEP 3. Adjust the line pressure.
Adjust the line pressure. Then check the symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 4.
STEP 4. Disassemble and clean the valve body.
Check the O-ring installation bolts for looseness and the valve body for damage. Repair or replace the faulty parts.
Replace the valve body assembly if the damage is too extensive. Then check the symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 6.
STEP 5. Replace the PCM.
1) Replace the PCM. When the PCM is replaced, register the encrypted code.
2) Test drive the vehicle.
3) Check for A/T diagnostic trouble code.
Q: Were any A/T DTCs set?
YES: Go to Step 6.
NO: The procedure is complete.
STEP 6. Overhaul the A/T.
1) Replace the following parts.
^ If DTC P1779 (P0731), DTC P1780 (P0732), or DTC P1781 (P0733) are set individually or in a group, replace the underdrive clutch.
^ If DTC P1781 (P0733), DTC P1782 (P0734) or DTC P1783 (P0735) [5A/T] are set individually or in a group, replace the overdrive clutch.
^ If DTC P1784 (P0736) is set, replace the reverse clutch.
^ If DTC P1779 (P0731) or DTC P1784 (P0736) are set individually or in a group, replace the low-reverse brake.
^ If DTC P1780 (P0732), DTC P1782 (P0734) [4A/T] or DTC P1783 (P0735) [5A/T] are set individually or in a group, replace the second brake.
^ If DTC P1779 (P0731), DTC P1780 (P0732) [5A/T] or DTC P1781 (P0733) [5A/T] are set, replace the one-way clutch.
^ If DTC P1782 (P0734) or DTC P1783 (P0735) are set individually or in a group, replace the direct clutch.
^ If DTC P1779 (P0731), DTC P1780 (P0732), DTC P1781 (P0733) or DTC P1784 (P0736) are set individually or in a group, replace the reduction brake [5A/T].
2) Test drive the vehicle.
3) Check for A/T diagnostic trouble code.
Q: Are any A/T DTCs set again?
YES: An A/T DTC may have set due to external radio frequency interference (RFI) possibly caused by cellular phone activity, or aftermarket components installed on the vehicle.
NO: The procedure is complete.
OBD-II DRIVE CYCLE PATTERN [DTC P1780 (P0732)]
Start the engine, and drive at 30 km/h (19 mph) or more for 10 seconds, with 2nd gear fixed (2nd gear in sport mode).
^ DTC P1773 (P0753): Low-reverse solenoid malfunction
^ DTC P1774 (P0758): Underdrive solenoid malfunction
^ DTC P1775 (P0763): Second solenoid malfunction
^ DTC P1776 (P0768): Overdrive solenoid malfunction
^ DTC P1777 (P0773): Reduction solenoid malfunction [5A/T]
^ DTC P1788 (P1751): A/T control relay malfunction
Sensor (The sensor below is determined to be normal)
^ Input shaft speed sensor
^ Output shaft speed sensor
^ Transmission range switch
^ Torque converter clutch solenoid
^ Low-reverse solenoid
^ Underdrive solenoid
^ Second solenoid
^ Overdrive solenoid
^ Reduction solenoid [5A/T]
^ A/T control relay
LOGIC FLOW CHARTS (Monitor Sequence) DTC P1781 (P0733):
DTC SET CONDITIONS [DTC P1781 (P0733)]
Check Conditions
^ Engine speed: 450 r/min or more.
^ Output speed: 900 r/min or more.
^ Shift stage: 3rd gear.
^ Input speed: more than 0 r/min.
^ Transmission fluid temperature sensor voltage: 4.5 volts or less.
^ Voltage of battery: 10 volts or more.
^ Transmission range switch rationality: only one signal.
^ Time after shift changing finish: 2 seconds or more.
Judgement Criteria
^ Output speed: [(input speed + 200 r/min) 3rd gear ratio] or more. (4 seconds)
^ Output speed: [(input speed - 200 r/min) 3rd gear ratio] or less. (4 seconds)
DESCRIPTIONS OF MONITOR METHODS [DTC P1782 (P0734)]
^ In 4th gear, if a difference between turbine revolution and that value calculated from output revolution equals or exceeds specified value, PCM judges that step-out in 4th gear has occurred.
MONITOR EXECUTION [DTC P1782 (P0734)]
^ Continuous
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR) [DTC P1782 (P0734)]
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
^ DTC P1770, P1771 (P0705): Transmission range switch malfunction
^ DTC P1766 (P0715): Input shaft speed sensor malfunction
^ DTC P1767 (P0720): Output shaft speed sensor malfunction
^ DTC P1778 (P0743): Torque converter clutch solenoid malfunction
^ If DTC P1781 (P0733) is set consecutively four times, the transaxle is locked into 3rd gear as a fail-safe measure, and the "N" range light flashes once per second.
OBD-II DRIVE CYCLE PATTERN [DTC P1781 (P0733)]
Start the engine, and drive at 40 km/h (25 mph) or more for 10 seconds, with 3rd gear fixed (3rd gear in sport mode).
^ DTC P1773 (P0753): Low-reverse solenoid malfunction
^ DTC P1774 (P0758): Underdrive solenoid malfunction
^ DTC P1775 (P0763): Second solenoid malfunction
^ DTC P1776 (P0768): Overdrive solenoid malfunction
^ DTC P1777 (P0773): Reduction solenoid malfunction [5A/T]
^ DTC P1788 (P1751): A/T control relay malfunction
Sensor (The sensor below is determined to be normal)
^ Input shaft speed sensor
^ Output shaft speed sensor
^ Transmission range switch
^ Torque converter clutch solenoid
^ Low-reverse solenoid
^ Underdrive solenoid
^ Second solenoid
^ Overdrive solenoid
^ Reduction solenoid [5A/T]
^ A/T control relay
LOGIC FLOW CHARTS (Monitor Sequence) DTC P1782 (P0734):
DTC SET CONDITIONS [DTC P1782 (P0734)]
Check Conditions
^ Engine speed: 450 r/min or more.
^ Output speed: 900 r/min or more.
^ Shift stage: 4th gear.
^ Input speed: more than 0 r/min.
^ Transmission fluid temperature sensor voltage: 4.5 volts or less.
^ Voltage of battery: 10 volts or more.
^ Transmission range switch rationality: only one signal.
^ Time after shift changing finish: 2 seconds or more.
Judgement Criteria
^ Output speed: [(input speed + 200 r/min) 4th gear ratio] or more. (4 seconds)
^ Output speed: [(input speed - 200 r/min) 4th gear ratio] or less. (4 seconds)
DESCRIPTIONS OF MONITOR METHODS [DTC P1783 (P0735)] [5A/T]
^ In Ruth gear, if a difference between turbine revolution and that value calculated from output revolution equals or exceeds specified value, PCM judges that step-out in reverse gear has occurred.
MONITOR EXECUTION [DTC P1783 (P0735)] [5A/T]
^ Continuous
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR) [DTC P1783 (P0735)] [5A/T]
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
^ DTC P1770 (P0705): Transmission range switch malfunction (Open circuit)
^ DTC P1771 (P0705): Transmission range switch malfunction (Short circuit)
^ DTC P1766 (P0715): Input shaft speed sensor malfunction
^ DTC P1767 (P0720): Output shaft speed sensor malfunction
^ If DTC P1782 (P0734) is set consecutively four times, the transaxle is locked into 3rd gear as a fail-safe measure, and the "N" range light flashes once per second.
OBD-II DRIVE CYCLE PATTERN [DTC P1782 (P0734)]
Start the engine, and drive at 40 km/h (25 mph) or more for 10 seconds, with 4th gear fixed (4th gear in sport mode).
^ DTC P1778 (P0743): Torque converter clutch solenoid malfunction
^ DTC P1773 (P0753): Low-reverse solenoid malfunction
^ DTC P1774 (P0758): Underdrive solenoid malfunction
^ DTC P1775 (P0763): Second solenoid malfunction
^ DTC P1776 (P0768): Overdrive solenoid malfunction
^ DTC P1777 (P0773): Reduction solenoid malfunction
^ DTC P1788 (P1751): A/T control relay malfunction
Sensor (The sensor below is determined to be normal)
^ Input shaft speed sensor
^ Output shaft speed sensor
^ Transmission range switch
^ Torque converter clutch solenoid
^ Low-reverse solenoid
^ Underdrive solenoid
^ Second solenoid
^ Overdrive solenoid
^ Reduction solenoid
^ A/T control relay
LOGIC FLOW CHARTS (Monitor Sequence) DTC P1783 (P0735):
DTC SET CONDITIONS [DTC P1783 (P0735)] [5A/T]
Check Conditions
^ Engine speed: 450 r/min or more.
^ Output speed: 900 r/min or more.
^ Shift stage: Ruth gear.
^ Input speed: more than 0 r/min.
^ Transmission fluid temperature sensor voltage: 4.5 volts or less.
^ Voltage of battery: 10 volts or more.
^ Transmission range switch rationality: only one signal.
^ Time after shift changing finish: 2 seconds or more.
Judgement Criteria
^ Output speed: [(input speed + 200 r/min) Ruth gear ratio] or more. (4 seconds)
^ Output speed: [(input speed - 200 r/min) Ruth gear ratio] or less. (4 seconds)
DESCRIPTIONS OF MONITOR METHODS [DTC P1784 (P0736)]
^ In reverse gear, if a difference between turbine revolution and that value calculated from output revolution equals or exceeds specified value, PCM judges that step-out in reverse gear has occurred.
MONITOR EXECUTION [DTC P1784 (P0736)]
^ Continuous
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR) [DTC P1784 (P0736)]
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
^ DTC P1770, P1771 (P0705): Transmission range switch malfunction
^ DTC P1766 (P0715): Input shaft speed sensor malfunction
^ DTC P1767 (P0720): Output shaft speed sensor malfunction
^ If DTC P1782 (P0734) is set consecutively four times, the transaxle is locked into 3rd gear as a fail-safe measure, and the selector lever position indicator light (D, 1 through 4 or 5) flashes once per second.
OBD-II DRIVE CYCLE PATTERN [DTC P1783 (P0735)] [5A/T]
Start the engine, and drive at 50 km/h (31 mph) or more for 10 seconds, with Ruth gear fixed Ruth gear in sport mode).
^ DTC P1778 (P0743): Torque converter clutch solenoid malfunction
^ DTC P1773 (P0753): Low-reverse solenoid malfunction
^ DTC P1774 (P0758): Underdrive solenoid malfunction
^ DTC P1775 (P0763): Second solenoid malfunction
^ DTC P1776 (P0768): Overdrive solenoid malfunction
^ DTC P1777 (P0773): Reduction solenoid malfunction [5A/T]
^ DTC P1788 (P1751): A/T control relay malfunction
Sensor (The sensor below is determined to be normal)
^ Input shaft speed sensor
^ Output shaft speed sensor
^ Transmission range switch
^ Torque converter clutch solenoid
^ Low-reverse solenoid
^ Underdrive solenoid
^ Second solenoid
^ Overdrive solenoid
^ Reduction solenoid [5A/T]
^ A/T control relay
LOGIC FLOW CHARTS (Monitor Sequence) DTC P1784 (P0736):
DTC SET CONDITIONS [DTC P1784 (P0736)]
Check Conditions
^ Engine speed: 450 r/min or more.
^ Output speed: 100 r/min or more.
^ Shift stage: reverse gear.
^ Input speed: more than 0 r/min.
^ Transmission fluid temperature sensor voltage: 4.5 volts or less.
^ Voltage of battery: 10 volts or more.
^ Transmission range switch rationality: only one signal.
^ Time after shift changing finish: 0.5 second or more.
Judgement Criteria
^ Output speed: [(input speed + 200 r/min) reverse gear ratio] or more. (1 second)
^ Output speed: [(input speed - 200 r/min) / reverse gear ratio] or less. (1 second)
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)
^ Malfunction of the input shaft speed sensor
^ Malfunction of the output shaft speed sensor
^ Malfunction of the PCM
^ Malfunction of the underdrive clutch retainer
^ If DTC P1784 (P0736) is set consecutively four times, the transaxle is locked into 3rd gear as a fail-safe measure, and the "N" range light flashes once per second.
OBD-II DRIVE CYCLE PATTERN [DTC P1784 (P0736)]
Start the engine, and drive in "R" range at 15 km/h (9 mph) or more for 10 seconds.
^ Malfunction of the transfer drive gear or driven gear [4A/T]
^ Malfunction of the direct planetary carriers [5A/T]
^ Malfunction of clutch system and / or brake system
^ Malfunction of the valve body
^ Malfunction of the accumulator
^ Electrical noise generated
DIAGNOSIS
Required Special Tool:
^ MB991958: Scan Tool (M.U.T-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: M.U.T-III USB Cable
^ MB991910: M.U.T-III Main Harness A
STEP 1. Using scan tool MB991958, read the A/T diagnostic trouble code.
CAUTION
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Check for A/T diagnostic trouble code.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC set?
YES [DTC P1766 set]: Refer to DTC P1766: Input Shaft Speed Sensor System. P1766
YES [DTC P1767 set]: Refer to DTC P1767: Output Shaft Speed Sensor System. P1767
YES [DTC P1773 set]: Refer to DTC P1773: Wherever Solenoid Valve System. P1773
YES [DTC P1774 set]: Refer to DTC P1774: Underdrive Solenoid Valve System. P1774
YES [DTC P1775 set]: Refer to DTC P1775: Second Solenoid Valve System. P1775
YES [DTC P1776 set]: Refer to DTC P1776: Overdrive Solenoid Valve System. P1776
YES [DTC P1777 (P0773) set]: DTC P1777 (P0773): Reduction Solenoid Valve System [5A/T]. P1777
NO: Go to Step 2.
STEP 2. Check the hydraulic pressure.
Each hydraulic pressure of the elements below, which DTCs indicate, should be within the standard value.
^ DTC P1779 (P0731): Underdrive clutch, low-reverse brake and reduction brake [5A/T]
^ DTC P1780 (P0732): Underdrive clutch, second brake and reduction brake [5A/T]
^ DTC P1781 (P0733): Underdrive clutch, overdrive clutch and reduction brake [5A/T]
^ DTC P1782 (P0734): Overdrive clutch, underdrive clutch [5A/T] second brake [4A/T] and direct clutch [5A/T]
^ DTC P1783 (P0735) [5A/T]: Overdrive clutch, second brake and direct clutch
^ DTC P1784 (P0736): Reverse clutch and low-reverse brake
Q: Are the hydraulic pressures within the standard value range?
YES: Go to Step 5.
NO [out of the range in one place]: Go to Step 4.
NO [out of the range in all places]: Go to Step 3.
STEP 3. Adjust the line pressure.
Adjust the line pressure. Then check the symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 4.
STEP 4. Disassemble and clean the valve body.
Check the O-ring installation bolts for looseness and the valve body for damage. Repair or replace the faulty parts.
Replace the valve body assembly if the damage is too extensive. Then check the symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 6.
STEP 5. Replace the PCM.
1) Replace the PCM. When the PCM is replaced, register the encrypted code.
2) Test drive the vehicle.
3) Check for A/T diagnostic trouble code.
Q: Were any A/T DTCs set?
YES: Go to Step 6.
NO: The procedure is complete.
STEP 6. Overhaul the A/T.
1) Replace the following parts.
^ If DTC P1779 (P0731), DTC P1780 (P0732), or DTC P1781 (P0733) are set individually or in a group, replace the underdrive clutch.
^ If DTC P1781 (P0733), DTC P1782 (P0734) or DTC P1783 (P0735) [5A/T] are set individually or in a group, replace the overdrive clutch.
^ If DTC P1784 (P0736) is set, replace the reverse clutch.
^ If DTC P1779 (P0731) or DTC P1784 (P0736) are set individually or in a group, replace the low-reverse brake.
^ If DTC P1780 (P0732), DTC P1782 (P0734) [4A/T] or DTC P1783 (P0735) [5A/T] are set individually or in a group, replace the second brake.
^ If DTC P1779 (P0731), DTC P1780 (P0732) [5A/T] or DTC P1781 (P0733) [5A/T] are set, replace the one-way clutch.
^ If DTC P1782 (P0734) or DTC P1783 (P0735) are set individually or in a group, replace the direct clutch.
^ If DTC P1779 (P0731), DTC P1780 (P0732), DTC P1781 (P0733) or DTC P1784 (P0736) are set individually or in a group, replace the reduction brake [5A/T].
2) Test drive the vehicle.
3) Check for A/T diagnostic trouble code.
Q: Are any A/T DTCs set again?
YES: An A/T DTC may have set due to external radio frequency interference (RFI) possibly caused by cellular phone activity, or aftermarket components installed on the vehicle.
NO: The procedure is complete.