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Isuzu Owners Maintenance and Repair - READ ONLY

3299 messages,  Last post on Dec 20, 2011 at 8:53 AM

You are in the Isuzu Trooper Forum.

What is this discussion about? Isuzu Ascender, Isuzu Trooper, SUV

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Messages Page 305 of 331

#3038 of 3299 Re: 2001 Trooper TOD problems [jgomez123] by atfdmike

Jun 26, 2006 (3:00 am)

Replying to: jgomez123 (Jun 25, 2006 7:51 pm)
Hi, I am not personally familiar with the TOD system, but the manual says it has a memory if codes are set from it. I hope this info helps. If there are codes, post them and we may be able to provide more info. Good luck.
2001 Isuzu Truck Trooper LTD 4WD V6-3.5L
 Vehicle Level Brakes and Traction Control Antilock Brakes / Traction Control Systems Testing and Inspection Torque On Demand (TOD) System Description of On-Board Diagnostics Precautions on Fault Diagnosis
 Precautions on Fault Diagnosis
  Replacement of Control Unit
The control unit itself rarely fails. In most cases, the harnesses have failed (e.q. short-circuit) to cause secondary troubles. Other cases include that the cause has been unknown due to intermittent occurrence of troubles and the troubles are removed accidentally along with replacement of control unit, resulting in misjudgment of cause. Therefore, before replacing the control unit, check the connector joints and whether the unspecified current flows in the control unit due to short-circuit between harnesses.
 
Trouble Intermittently Observed
Troubles intermittently observed are mostly attributable to temporary imperfect connection of harnesses and connectors.
When such troubles are found, check the associated circuit according to the following procedure.
 
Check whether improper connectors are plugged in or connector terminals are completely engaged.
Check whether the terminals are deformed or damaged. If yes, remove the deformation or damage and connect the terminals securely.
It is likely that wires in the harness are falsely broken. Therefore, in examination of failed harness circuit, shake the harness for check to such extent that the harness will not be damaged.
Test Run of Filed TOD Vehicle
If the TOD indicator lamps experienced faulty operation even once in the past, the failed portion can be identified by use of the procedure "Fault Diagnosis from Trouble Codes" or "Fault Diagnosis from Lighting Status of TOD Indicator Lamps". If the troubles that are only recognized as abnormal phenomena of the vehicle by the driver are observed, conduct the test run in the following procedure to reproduce the faulty phenomena and diagnose the fault for each phenomenon.
 
Start the engine, and check that the TOD indicator lamps are turned on for about two seconds for initial check; the CHECK lamp goes off; and the TOD indicator lamps display the specified drive mode. (If the CHECK lamp starts blinking, read the trouble codes and identify the failed portion. )
While keeping the vehicle standstill, operate the 4WD switch and shift the transfer lever to change the modes: 2H mode; TOD mode; 4L mode; TOD mode; 2H mode. Check that the TOD indicator lamps correctly display the status whenever the mode is changed. If the transition status is displayed during the shift operation, run the vehicle a little to complete shifting.
Slowly start the vehicle in the TOD mode, and add the power to accelerate to at least 40 km/h (25 mph) and maintain the speed for about two minutes. Apply the brake to completely stop the vehicle. Repeat this test pattern at least three times.
Turn the steering to the right end (or left end) in the TOD mode, and slowly start the vehicle and make a circle five times. Next, conduct the same test in the 2H mode.
Slowly start the vehicle in the TOD mode, and accelerate to at least 40 km/h (25 mph) . Keep the established speed, carefully change the mode in the sequence "TOD mode; 2H mode; TOD mode" while checking that the shift is complete in each mode change. After the test, apply the brake to completely stop the vehicle.
Slowly start the vehicle in the TOD mode, and accelerate to at least 40 km/h (25 mph) . Apply the brake strongly so that the ABS works, and completely stop the vehicle.
Slowly start the vehicle in the 4L mode, and accelerate to at least 20 km/h (12 mph) . Apply the brake to completely stop the vehicle. If the CHECK lamp starts blinking during the test run, read the trouble codes and give appropriate maintenance according to the fault diagnostic procedure. If the TOD indicator lamps are lit abnormally during the run, check the lighting condition and give appropriate maintenance according to the fault diagnostic procedure. Even if the phenomena are not observed, try to reproduce the abnormal state reported by the customer to the possible extent.
Post-Repair Check
As long as the starter is not turned off, the TOD indicator lamps continue blinking even after the failed control unit is repaired. Therefore, upon completion of repair, be sure to turn off the starter switch once and then turn on it to conduct the test run sequence specified in steps 1 through 6 above and check that the TOD indicator lamps no longer show any faulty status.
 
TOD Indicator Control
The TOD indicator on the instrument panel informs the driver of the current working status of the transfer unit. The information consists of two items: the drive mode (2H, TOD, 4L, transition) and the torque split status of the TOD (torque distribution level). The indicator can display occasional errors and corresponding error codes.
To check for codes stored:
The control unit has a function of self-diagnosis. If a trouble occurs in the course of system start-up, the control unit blinks the CHECK lamp and saves the trouble code.
 
Note: If an intermittent fault occurs, the control unit stops blinking upon removal of the fault. The trouble code is saved to the control unit.
 
Indication Method of Trouble Code
 
Short-circuit terminal 8 of the self-diagnostic connector to GND to display the trouble code on the CHECK lamp.
If no trouble codes exist, code "12" is displayed continuously.
  
If trouble codes exist, code "12" is displayed three times, and the trouble codes, starting from the smaller code number, are displayed three times respectively.
 
Here is a link to the aldl connector pin locations.
 
http://www.carspace.com/atfdmike/.59a64997!v=
 
Good luck.

#3039 of 3299 Re: 2001 Trooper TOD problems [atfdmike] by Mr_Shiftright HOST

Jun 26, 2006 (9:50 am)

Replying to: atfdmike (Jun 26, 2006 3:00 am)
Thanks for the helpful post Mike and for supporting the forums.
 
MrShiftright
Host

#3040 of 3299 Re: 2001 Trooper TOD problems [Mr_Shiftright] by jgomez123

Jun 26, 2006 (8:49 pm)

Replying to: Mr_Shiftright (Jun 26, 2006 9:50 am)
Okay I checked the codes and this is what I found. The first code is 14 and the second code is 24. I am not sure what they belong too. Can anyone provide assistance. I also noticed today that a better discription of the problem is: Whenever I am below 13 mph the TOD lights up all four wheels SOLID then when I begin to pick up speed the lights start to flash. After about 20 mph the TOD flashes 2L and after a couple of flashes (3 or 4) 2L stays on solid. The weird part is that the Check light is not coming on at all.
 
Thanks for the help!

#3041 of 3299 Re: 2001 Trooper TOD problems [jgomez123] by atfdmike

Jun 27, 2006 (9:02 am)

Replying to: jgomez123 (Jun 26, 2006 8:49 pm)
Hi again, found this:
 
2001 Isuzu Truck Trooper LTD 4WD V6-3.5L
 Vehicle Level Brakes and Traction Control Antilock Brakes / Traction Control Systems Testing and Inspection Antilock Brake System Trouble Code Diagnostic Procedures By Diagnostic Trouble Code (DTC) Number DTC 14 - B-2 EHCU Abnormality
  
  
DTC 14 - B-2 EHCU Abnormality
  
By Diagnostic Trouble Code (DTC) Number
  http://www.carspace.com/atfdmike/.59a65b3a!v=
  
 2001 Isuzu Truck Trooper LTD 4WD V6-3.5L
 Vehicle Level Brakes and Traction Control Antilock Brakes / Traction Control Systems Testing and Inspection Antilock Brake System Trouble Code Diagnostic Procedures By Diagnostic Trouble Code (DTC) Number DTC 24 - B7 Transfer Monitor
  
  
DTC 24 - B7 Transfer Monitor
  
By Diagnostic Trouble Code (DTC) Number
   
  
 http://www.carspace.com/atfdmike/.59a65b3b!v=
  
 http://www.carspace.com/atfdmike/.59a65b71!v=
 
  Okay, I found these, hope they help. also, just from experience, I know that your brake light switch is an integral part of the system and is monitored by the powertrain control module. You might check to see if it is adjusted correctly, if it is telling the tod module the brakes are on, it will effect the engagement speeds of the tod significantly. Just a tip that will at least eliminate one possible source of problems, particularly if it is intermittent.The TOD unit is under the passenger seat, might want to check the connector on that. Also, it monitors a speed sensor for the front driveshaft and another on the rear. Those connectors are on the transfer case near the the respective output shaft to the propeller shafts.
To me, it seems as though your TOD ECU is seeing some differences in speed from the front to rear, and applying torque to balance. If you want info on the speed sensors, Post again and I will dig deeper.
 Remember to disconnect the battery cable if you are going to disconnect and reconnect any connectors. I think these are pretty easy things to check and then go from there. Good luck.

#3042 of 3299 Re: 2001 Trooper TOD problems [atfdmike] by jgomez123

Jun 27, 2006 (9:54 am)

Replying to: atfdmike (Jun 27, 2006 9:02 am)
I understood all of that, but what does EHCU stand for and where is it located?

#3043 of 3299 Re: 2001 Trooper TOD problems [jgomez123] by tidester

Jun 27, 2006 (12:39 pm)

Replying to: jgomez123 (Jun 27, 2006 9:54 am)
EHCU = ElectroHydraulic Control Unit
 
I'm sure one of the owners will be able to tell you what it does and where to find it.
 
tidester, host

#3044 of 3299 Re: TOD FLUID [millejo1] by pacheaco

Jun 27, 2006 (6:21 pm)

Replying to: millejo1 (Apr 25, 2006 8:45 am)
I had the exact same thing happen, starter on friday, TOD flashing the next day. Did you get the check flashing to stop?

#3045 of 3299 Re: 2001 Trooper TOD problems [jgomez123] by atfdmike

Jun 28, 2006 (3:12 am)

Replying to: jgomez123 (Jun 27, 2006 9:54 am)
The ehcu is your antilock brake controller. I don't think that this is where your problem lies as long as you are not getting fault codes for the brake system. It does monitor wheel rotation, and I don't know how or if that information is used by the vehicle other than for stopping. The diagnosis chart just has you taking it out of the loop so to speak for a voltage check on one pin. Again, not a bad idea to carefully disconnect and inspect the connector, cleaning with contact cleaner if necessary.
Electronic Hydraulic Control Unit (EHCU)
The EHCU consists of ABS control circuits, fault detector, and a fail-safe. It drives the hydraulic unit according to the signal from each sensor, canceling ABS to return to normal braking when a malfunction has occurred in the ABS.
The EHCU has a self-diagnosing function which can indicate faulty circuits during diagnosis.
The EHCU is mounted on the engine compartment front right side. It consists of a Motor, Plunger Pump, Solenoid Valves and Check Valve.
On the outside, the relay box containing a motor relay and a valve relay is installed.
 
Solenoid Valves: Reduces or holds the caliper fluid pressure for each front disc brake or both rear disc brakes according to the signal sent from the EHCU.
Reservoir: Temporarily holds the brake fluid that returns from the front and rear disc brake caliper so that pressure of front disc brake caliper can be reduced smoothly.
Plunger Pump: Feeds the brake fluid held in the reservoir to the master cylinder.
Motor: Drives the pump according to the signal from EHCU.
Check Valve: Controls the brake fluid flow.
Hope this helps.

#3046 of 3299 98 Isuzu Trooper, 3.5l, 89k miles, Maintenance issues by eric138109

Jun 28, 2006 (4:48 am)

I’ve been good at changing the oil regularly but that's about it. Should I get the timing belt changed and the water pump at the same time? Are the troopers timing belts prone to breaking? What else should I get done? So far it runs great. Thanks in advance for your help!

#3047 of 3299 Re: 2001 Trooper TOD problems [atfdmike] by pacheaco

Jun 28, 2006 (2:12 pm)

Replying to: atfdmike (Jun 28, 2006 3:12 am)
Thank you very much. Before my starter died I had and continue to have this rubbing or grinding sound. It sounds like I have a low tire but I dont. Like the back tire is rubbing against something as it turns. Could it be the ABS. Also my flashing check TOD light goes off when I push the 4WD button on. Any ideas what the grinding/rubbing sound is? The tire pressures are good.

Messages Page 305 of 331

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