Rear Differential: Other Honda Pilot I

VTM-4 Indicator

The VTM-4 indicator comes on under certain conditions even if the 4WD system is working normally. Here are some examples

1. When you use high-powered wireless equipment such as a CB or Ham radio in the vehicle.
2. When you keep spinning the rear wheels while the vehicle is stuck in sand, mud, snow, with the VTM-4 indicator blinking, and detects DTC 76, continuing 4WD control at this time.
3. When the battery voltage suddenly drops below 8 volts or rises above 16 volts.

After the VTM-4 indicator comes on, it stays on until you turn the ignition switch off.

Initialization of the VTM-4 Control Unit

Whenever the VTM-4 control unit is replaced, it must be initialized to make the 4WD system function. There are two methods used to initialize the VTM-4 control unit. One method is to use the Honda Diagnostic System (HDS) with the appropriate software plugged into the 16P data link connector (DLC). The other method is to initialize the VTM-4 control unit manually.

Scheme 81

1. With the ignition switch OFF, connect the HDS to the 16P DLC (A) behind the driver's dashboard lower cover.
2. Turn the ignition switch ON (II), and follow the prompts on the HDS screen.

Scheme 82

1. Start the engine (the VTM-4 indicator comes on, and the VTM-4 lock indicator is off).
2. Apply the brakes, and move the shift lever to either the R, 1, or 2 position, then push the VTM-4 lock switch (the VTM-4 indicator stays on, and the VTM-4 lock indicator is on). The 4WD system is now in lock mode.
3. Turn the ignition switch off.
4. Turn the ignition switch ON (II) (the VTM-4 indicator and the VTM-4 lock indicator both come on for 4 seconds, then go off). The VTM-4 control unit is initialized.

How to Check for DTCs

When the VTM-4 control unit senses an abnormality in the input or output systems, the VTM-4 indicator in the gauge assembly will usually come on, and the malfunction indicator lamp (MIL), the D5 indicator and/or the ABS indicator may also come on.

There are two methods used to check for DTCs. One method is to use the HDS with the appropriate software plugged into the 16P data link connector (DLC). The other method is to connect the service check signal (SCS) circuit with the HDS. When the 16P DLC is connected to the HDS, the VTM-4 indicator will blink the diagnostic trouble code (DTC) when the ignition switch is turned ON (II) and the SCS circuit is connected to body ground.

Scheme 83

1. With the ignition switch OFF, connect the HDS to the 16P DLC (A) behind the driver's dashboard lower cover.
2. Turn the ignition switch ON (II), and follow the prompts on the HDS to display the DTC(s) on the screen. After determining the DTC(s), refer to the DTC Troubleshooting Index.
3. If there are fuel and emissions DTCs, A/T DTCs, and ABS DTC's at the same time, troubleshoot the fuel and emission DTCs first.
4. After recording the DTCs, clear all DTCs.
5. Test-drive the vehicle for several minutes in 4WD mode, and check for DTCs. If the DTC returns, refer to the DTC Troubleshooting Index. If the DTC does not return, there was an intermittent problem within the circuit. Make sure all connectors and terminals in the circuit are tight.

Scheme 84

1. Park the vehicle on level ground. Shift to the P position, then turn off the engine.
2. Release the parking brake pedal.
3. With the ignition switch OFF, connect the HDS to the 16P DLC (A) behind the driver's dashboard lower cover.
4. Connect the SCS circuit to body ground using the HDS.
5. Turn the ignition switch ON (II), and observe the VTM-4 indicator.
6. Record all the DTC(s), then refer to the DTC Troubleshooting Index to determine the meaning of each DTC.
7. Clear the DTCs from the VTM-4 control unit memory (refer to «How to Clear the VTM-4 Control Unit Memory»(ref-174019-S18085462632005041500000) ).
8. If the MIL, D5 indicator, and the ABS indicator all come on at the same time, troubleshoot the cause for the MIL first.
9. Test-drive the vehicle for several minutes in 4WD mode, and check for DTCs. If the DTC returns, refer to the DTC Troubleshooting Index. If the DTC does not return, there was an intermittent problem within the circuit. Make sure all connectors and terminals in the circuit are tight.

How to Clear the VTM-4 Control Unit Memory

There are two methods used to clear DTCs from the VTM-4 control unit memory. One method is to use the HDS with the appropriate software plugged into the 16P data link connector (DLC). The other method is to connect the service check signal (SCS) connector with the HDS, and manually clear the memory.

Scheme 85

1. With the ignition switch OFF, connect the HDS to the 16P DLC (A) behind the driver's dashboard lower cover.
2. Turn the ignition switch ON (II), and follow the prompts on the HDS screen to clear the DTC(s).

Scheme 86

1. Park the vehicle on level ground. Shift to the P position, then turn off the engine.
2. Release the parking brake pedal.
3. With the ignition switch OFF, connect the HDS to the 16P DLC (A) behind the driver's dashboard lower cover.
4. Connect the SCS circuit to body ground using the HDS.
5. Turn the ignition switch ON (II).
6. The VTM-4 indicator comes on and stays on for 4 seconds. Press and hold the VTM-4 lock switch while the VTM-4 indicator is on.
7. When the VTM-4 indicator goes off, release the VTM-4 lock switch.
8. The VTM-4 indicator comes on and stays on for 4 seconds. Press and hold the VTM-4 lock switch while the VTM-4 indicator is on.
9. When the VTM-4 indicator goes off, release the VTM-4 lock switch. The VTM-4 indicator will make two short blinks to confirm that the DTCs have been cleared from the VTM-4 control unit memory.
10. Turn the ignition switch OFF, then disconnect the HDS from the 16P DLC.

VTM-4 Control Unit Inputs & Outputs

The VTM-4 control unit terminal voltage and measuring conditions for the 4WD control system are shown.

Scheme 87

Scheme 88

Scheme 89

Scheme 90

Scheme 91

Scheme 92

The VTM-4 LOCK indicator does not come on when the VTM-4 lock switch is pushed

Note. The VTM-4 LOCK indicator will only come on when the engine is running and the transmission is in R, 1, or 2 before the switch is pressed.

Scheme 93

Scheme 94

Scheme 95

Scheme 96

Scheme 97

1. Check the No. 9 (10A) fuse in the driver's under-dash fuse/relay box. Is the fuse OK? YES - Go to step 2. NO - Replace the fuse, and recheck.
2. Turn the ignition switch ON (II), and watch the VTM-4 LOCK indicator. Does the VTM-4 LOCK indicator come on with the ignition switch ON (II), and does it go off 4 seconds later? YES - Go to step 3. NO - Go to step 10 .
3. Start the engine, and move the shift lever to the R, 1, and 2 positions, then watch the VTM-4 LOCK indicator. Does the VTM-4 LOCK indicator come on when the VTM-4 lock switch is pushed? YES - The system is OK at this time. NO - Go to step 4.
4. Check for an A/T system DTC. Is there a DTC? YES - Troubleshoot the A/T system for the cause of the DTC (refer to page 14-7). NO - Go to step 5.
5. Turn the ignition switch OFF.
6. Disconnect the A (22P) and B (26P) connectors from the VTM-4 control unit.
7. Turn the ignition switch ON (II).
8. Connect a voltmeter between the B11 terminal of the VTM-4 control unit and body ground. Is there battery voltage when the VTM-4 lock switch is pushed? YES - Check for loose terminal fit in the VTM-4 control unit connectors. If it is normal, replace the VTM-4 control unit. NO - Go to step 9.
9. Test the VTM-4 lock switch (see «VTM-4 Lock Switch Test/Replacement»(ref-174019-S09310024272005041500000) ). Is the VTM-4 lock switch OK? YES - Repair open in the wire between the VTM-4 lock switch and the VTM-4 control unit. NO - Replace the VTM-4 lock switch.
10. Connect the B9 terminal of the VTM-4 control unit to body ground with a jumper wire, and watch the VTM-4 LOCK indicator. Does the VTM-4 LOCK indicator come on? YES - Check for loose terminal fit in the VTM-4 control unit connectors. If it is normal, replace the VTM-4 control unit. NO - Go to step 11.
11. Turn the ignition switch OFF.
12. Remove the VTM-4 lock switch.
13. Connect the No. 5 terminal of the VTM-4 lock switch 5P connector to body ground with a jumper wire. Check the continuity between the B9 terminal and body ground. Is there continuity? YES - Go to step 14. NO - Repair open in the wire between the B9 terminal and the VTM-4 lock switch.
14. Turn the ignition switch ON (II).
15. Measure the voltage between the No. 2 terminal of the VTM-4 lock switch 5P connector and body ground. Is there battery voltage? YES - Replace the VTM-4 LOCK indicator bulb. NO - Repair open in the wire between the No. 2 terminal of the VTM-4 lock switch 5P connector and the driver's under-dash fuse/relay box.

Scheme 98

1. Disconnect the B (26P) connector from the VTM-4 control unit.
2. Turn the ignition switch ON (II), and watch the VTM-4 LOCK indicator. Does the VTM-4 LOCK indicator come on with the ignition switch ON (II)? YES - Go to step 3. NO - Check for loose terminal fit in the VTM-4 control unit connectors. If it is normal, replace the VTM-4 control unit.
3. Turn the ignition switch OFF.
4. Disconnect the VTM-4 lock switch connector.
5. Check for continuity between the B9 terminal of the VTM-4 control unit and body ground. Is there continuity? YES - Repair short to ground in the wire between the B9 terminal of the VTM-4 control unit and the VTM-4 lock switch. NO - Replace the VTM-4 lock switch.

Scheme 99

Scheme 100

Scheme 101

Scheme 102

1. Disconnect the B (26P) connector from the VTM-4 control unit.
2. Turn the ignition switch ON (II).
3. Connect the B9 terminal of the VTM-4 control unit to body ground with a jumper wire, and watch the VTM-4 LOCK indicator. Does the VTM-4 LOCK indicator come on? YES - Check for loose terminal fit in the VTM-4 control unit connectors. If it is normal, replace the VTM-4 control unit. NO - Go to step 4.
4. Turn the ignition switch OFF.
5. Remove the VTM-4 lock switch.
6. Connect the No. 5 terminal of the VTM-4 lock switch 5P connector to body ground with a jumper wire. Check for continuity between the B9 terminal and body ground. Is there continuity? YES - Go to step 7. NO - Repair open in the wire between the B9 terminal of the VTM-4 control unit and the VTM-4 lock switch.
7. Turn the ignition switch ON (II).
8. Measure the voltage between the No. 2 terminal of the VTM-4 lock switch 5P connector and body ground. Is there battery voltage? YES - Replace the VTM-4 LOCK indicator bulb. NO - Repair open in the wire between the No. 2 terminal of the VTM-4 lock switch 5P connector and the driver's under-dash fuse/relay box.

Scheme 103

1. With the vehicle on level ground, inspect the differential fluid with the ignition switch OFF.
2. Remove the oil filler plug (A) and sealing washer (B), then check the condition of the fluid, and make sure the fluid is at the proper level (C).
3. The fluid level must be up to the fill hole. If it is below the hole, add the recommended fluid until it runs out, then reinstall the oil filler plug with a new sealing washer.
4. If the differential fluid is dirty, remove the drain plug (D) and sealing washer (B), then drain the fluid.
5. Clean the drain plug, then reinstall with a new washer, and refill the differential with the recommended fluid to the proper level. Fluid capacity: 2.64 l (2.79 US. Qt) at oil change Recommended fluid: VTM-4 Differential Fluid
6. Reinstall the oil filler plug with a new washer.

Scheme 104

Scheme 105

Scheme 106

1. Lift up the vehicle so all four wheels are off the ground (see «LIFT & SUPPORT POINTS»(ref-173978-S25863771862005041500000) ).
2. Remove the rear wheels.
3. Turn the ignition switch OFF with the shift lever in the P position.
4. Release the parking brake.
5. Disconnect the left clutch electromagnetic coil 2P connector (a) and the right clutch electromagnetic coil 6P connector (B).
6. Using a click-type torque wrench set at 20 N.m (2.0 kgf.m, 15 ft. lbs.), turn each rear hub clockwise. If both hubs turn without the torque wrench clicking, the differential is OK. If the torque wrench clicks while turning either hub, the rear differential is faulty, replace it.

Scheme 107

Scheme 108

1. Lift up the vehicle so all four wheels are off the ground (see «LIFT & SUPPORT POINTS»(ref-173978-S25863771862005041500000) ).
2. Remove the rear wheels.
3. Turn the ignition switch OFF with the shift lever in the P position.
4. Release the parking brake.
5. Disconnect the left clutch electromagnetic coil 2P connector (A) and the right clutch electromagnetic coil 6P connector (B). Left Clutch Electromagnetic Coil Test
6. Connect the battery power to the No. 1 terminal of the left clutch electromagnetic coil 2P connector (A) and ground to the No. 2 terminal. Right Clutch Electromagnetic Coil Test
7. Connect the battery power to the No. 6 (BRN) terminal of the right clutch electromagnetic coil 6P connector (B) and ground to the No. 3 (GRN) terminal.
8. Using a click-type torque wrench set at 200 N.m (20.4 kgf.m, 148 ft. lbs.), turn each rear hub clockwise. If the torque wrench clicks on both hubs, the differential is OK. If either hub turns, replace the rear differential.

Scheme 109

1. Remove the wire harness cover (A), then disconnect the differential oil temperature sensor 2P connector (B).
2. Remove the differential oil temperature sensor (C).
3. Install the differential oil temperature sensor (C) in the reverse order of removal, with a new O-ring (D).

Scheme 110

Scheme 111

1. Remove the control panel (see «DRIVER'S SWITCH PANEL REMOVAL/INSTALLATION»(ref-174030-S01226226162005042500000) ).
2. Disconnect the 5P connector from the VTM-4 lock switch, then remove the VTM-4 lock switch.
3. Check for continuity between the terminals in each switch position according to the table. If the switch fails any continuity check, replace the switch.