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Acura RL. Manual - part 272

NO - Return to step 8 and recheck. If the HDS indicates NOT COMPLETED, return to step 9 and
recheck.

DTC P1780: Problem in Shift Control System

1. Clear the DTC with the HDS.

2. Test-drive the vehicle for several minutes with the shift lever in D, and let the transmission shift through

all five gears, then slow down to a stop.

3. Turn the ignition switch to LOCK (0). Repeat step 2, then go to step 4.

4. Check for other DTCs indicated simultaneously with DTC P1780.

Are there other DTCs?

YES - Troubleshoot the problem indicated by the DTC.

NO - Go to step 5.

5. Update the A/T software in the PCM if it does not have the latest software (see UPDATING THE

PCM ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).

6. Test-drive the vehicle for several minutes with the shift lever in D, and let the transmission shift through

all five gears, then slow down to a stop.

7. Turn the ignition switch to LOCK (0). Repeat step 6, then go to step 8.

8. Check for DTC(s) in the DTCs/Freeze Data in A/T Mode Menu with the HDS.

Is DTC P1780 indicated?

YES - If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ),
then recheck. If the PCM was substituted, go to step 1.

NO - Go to step 9.

9. Monitor the OBD STATUS for P1780 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the HDS indicate PASSED?

YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the
original PCM (see PCM REPLACEMENT ). If any other DTCs were indicated on step 8, go to the

NOTE:

Before you troubleshoot, record all freeze data and any on-board snapshot, and
review General Troubleshooting Information (see GENERAL
TROUBLESHOOTING INFORMATION ).

NOTE:

DTC P1780 means there is one or more A/T DTCs about the shift control
system.

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

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INDICATED DTC'S TROUBLESHOOTING.

NO - Check for poor connections and loose terminals at the PCM. If the PCM was updated, substitute a
known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the PCM was substituted, go to
step 1. If the HDS indicates NOT COMPLETED, return to step 6 and recheck.

ROAD TEST

1. Warm up the engine to normal operating temperature (the radiator fan comes on).

2. Apply the parking brake, and block all four wheels. Start the engine, then shift to D while pressing the

brake pedal. Press the accelerator pedal, and release it suddenly. The engine should not stall.

3. Repeat step 2 in all shift lever positions.

4. Connect the HDS to the DLC (A), and go to the A/T data list. If the HDS does not communicate with the

PCM, troubleshoot the DLC circuit; '05-07 models (see '05-07 MODELS ), '08 model (see '08
MODEL ).

Fig. 190: Identifying Data Link Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

5. Prepare the HDS to take a HIGH SPEED SNAPSHOT (refer to the HDS user's guide for more details if

needed):



Select High Speed icon.



Select these parameters:



VSS veh speed



Output Shaft (Countershaft) Speed



Input Shaft (Mainshaft) Speed (rpm)



RPM engine speed



Relative TP Sensor



APP Sensor A



ATF Temp sensor



Battery voltage

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

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

Shift control



Brake Switch



Set the Trigger Type to Parameter.



Adjust the Parameter setting to APP Sensor A above 0.75 V.



Set the recording time to 60 seconds.



Set the trigger point to -30 seconds.

6. Find a suitable level road. When you are ready to do the test, press OK on the HDS.

7. Monitor the HDS, and accelerate quickly until the APP Sensor A reads 0.75 V. Maintain a steady throttle

until the transmission shifts to 5th gear, then slow the vehicle and come to a stop.

8. Save the snapshot if the entire event was recorded, or increase the recording time setting as necessary,

and repeat step 7.

9. Adjust the parameter setting to 2.25 V. Test-drive the vehicle again. While monitoring the HDS,

accelerate quickly until the APP Sensor A reads 2.25 V. Maintain a steady throttle until the transmission
shifts to 5th gear (or reasonable speed), then slow the vehicle and come to a stop.

10. Save the snapshot if the entire event was recorded, or increase the recording time setting as necessary,

and repeat step 9.

11. Accelerate quickly until the accelerator pedal is to the floor. Maintain a steady pedal until the

transmission shifts to 3rd gear, then slow to a stop, and save the snapshot.

12. Review each snapshot individually, and compare the Shift Command, the APP Sensor A voltage, and the

Vehicle Speed to the table below.

Upshift: D Position

VEHICLE SPEED - UPSHIFT D POSITION

Accelerator pedal position sensor voltage: 0.75 V
1st-->2nd

9-10 mph (14-16 km/h)

2nd-->3rd

15-17 mph (24-28 km/h)

3rd-->4th

23-27 mph (37-43 km/h)

4th-->5th

42-46 mph (68-74 km/h)

Lock-up ON

48-51 mph (77-82 km/h)

Accelerator pedal position sensor voltage: 2.25 V
1st-->2nd

23-25 mph (37-41 km/h)

2nd-->3rd

45-48 mph (72-78 km/h)

3rd-->4th

65-68 mph (104-110 km/h)

4th-->5th

85-88 mph (136-142 km/h)

Lock-up ON

96-99 mph (154-160 km/h)

Fully-opened throttle
Accelerator pedal position sensor voltage: 4.5 V
1st-->2nd

34-38 mph (55-61 km/h)

2nd-->3rd

62-65 mph (99-105 km/h)

3rd-->4th

91-95 mph (147-153 km/h)

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

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Downshift: D Position (reference)

VEHICLE SPEED - DOWNSHIFT D POSITION

13. Drive the vehicle in 4th or 5th gear in the sequential sportshift mode in M, then downshift to 2nd gear.

The vehicle should immediately begin to slow down from engine braking.

14. Shift to R, accelerate from a stop at full throttle momentarily, and check for abnormal noise and clutch

slippage.

15. Park the vehicle on a slope (about 16 degrees), apply the brake, and shift into P. Release the brake; the

vehicle should not move.

STALL SPEED TEST

1. Make sure the transmission fluid is filled to the upper level (see ATF LEVEL CHECK ).

2. Apply the parking brake, and block all four wheels.

3. Connect the HDS to the DLC (A), and go to the A/T data list. If the HDS does not communicate with the

PCM, troubleshoot the DLC circuit; '05-07 models (see '05-07 MODELS ), '08 model (see '08
MODEL ).

Accelerator pedal position sensor voltage: 0.75 V
Lock-up OFF

45-48 mph (72-77 km/h)

5th-->4th

36-39 mph (58-62 km/h)

4th-->3rd

16-18 mph (25-29 km/h)

2nd-->1st

6-8 mph (9-13 km/h)

Accelerator pedal position sensor voltage: 2.25 V
Lock-up OFF

66-70 mph (107-113 km/h)

5th-->4th

56-59 mph (90-94 km/h)

4th-->3rd

30-33 mph (49-53 km/h)

3rd-->2nd

17-21 mph (28-34 km/h)

2nd-->1st

6-8 mph (9-13 km/h)

Fully-opened throttle
Accelerator pedal position sensor voltage: 4.5 V
4th-->3rd

83-86 mph (133-138 km/h)

3rd-->2nd

53-59 mph (86-94 km/h)

2nd-->1st

27-29 mph (43-47 km/h)

NOTE:

Always use the brake to hold the vehicle, when stopped on an incline in
gear. Depending on the grade of the incline, the vehicle could roll
backwards if the brake is released.

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

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