4x4s. They're a Breed apart. They're passion. They're poison.
Along with these special beasts that can go anywhere, Come their own perks and Maintenance.
And one fine day It happened....
I normally engaged 4H for my SUV and rather than Simple 4H light coming on, Both 4H & 4L lights came on together. Shoot!
Please note that checking all Images in this guide is of Utmost importance. Click on each pic and enlarge to read. Most of the guide is embedded into images itself.
Step 1: Running Basic Checks
The reason Both 4H & 4L lights came on Together is that 4x4 ECU detected some error and hence ECU is in Safe mode. Which also means that 4x4 will not work. My Heart started thumping. I have heard tales of Really expensive repair due to these errors on various forums. Although, many times its also a simple Moisture or Connection issue.
Before delving deep into 4x4 Mysteries, one can run these basic checks if they solve the problem-
1. Remove battery Negative. Press horn a few times and Reconnect in some time.
2. Check fuse box for T-case or 4x4 ECU fuses.
3. Remove 4x4 ECU connector, clean and refit
4. Rock the car Backwards-Forwards in a straight line with the ESOF switch in 2H. This should help disengage any stuck mechanism.
5. Rock The the vehicle while making Sharp turns (Don't overdo this)
6. Charge the vehicle battery on designated Battery charger overnight. Clean any carbon on Battery terminals.
7. Remove 4x4 Shift Motor connector, Clean and refit.
8. Lift the front wheels in air And check free spin. If the wheels do not spin Freely, the vehicle is in 4x4 and Should NOT BE DRIVEN on pavement, Otherwise extensive damage could occur.
9. Check for any wire cut or Rat bite on Associated Wiring.
10.Let The vehicle rest Overnight and retry in morning.
Step 2: Checking the ECU Error Code
Unfortunately, The basic checks did not solve my problem. So The next thing was to take the vehicle to the showroom for a through check. My front wheels were spinning freely so at-least it was safe to drive the vehicle.
Upon reaching the showroom, The guys insisted on checking errors using OBD-Scan tool. I explained that 4x4 has a separate ECU and cannot be checked using Main Engine ECU. What I got was a blank state. Even the head supervisor who looked after my vehicles for 20 years did not properly know about 4x4 System. What these showroom guys usually do is replace the entire setup including motors and ECU. That solves the problem but also proves to be way too expensive for what is a minor problem. (bills in range of 30~90K are common)
That made it clear that even the most reputed Auth. showrooms had no Knowledge of 4x4 systems. It was there I decided that I'll have to run all the troubleshooting myself. As Keeping the vehicles in hands of Showroom fools could cause more problems.
Read the images to understand how to check 4x4 ECU error code. Basically, a bulb is connected in particular fashion and the bulb blinks to give an error code (Like the Morse code). Using this code we can take further action.
The error in my case was 111. Which means shift motor position Switch. This will require complete removal of motor to check internal contacts.
Known problem areas for Safari/Scorpio 4x4 are-
1.Motor position switch (like mine)
2.Motor itself- A simple servicing and cleaning of carbon usually helps. Motor itself hardly ever shorts out as its protected by the ECU.
3. Speed Sensor. This will cause 4H to work but 4L will not engage and the sensor does not signal that car has Stopped.
4. Wiring harness- By rats or Other mess.
5. Connectors- Often there is dust or Moisture in connectors. Sometimes Errors will come up after driving through a puddle but solves with some WD40 & cleaning.
Step 3: Locating & Removing the Shift Motor
The motor is Located roughly in the center of entire Vehicle, Roughly towards driver side. Its behind the TransferCase. The motor is protected by thick metal guard. Removal of motor is quite a simple process as you see. Remove the battery -ve and T-case fuse before working on.
After removing the motor, you can visually check if T-case is stuck in 4x4. If so, use spanners to manually rotate the shaft into 2H. Cover up exposed connectors using plastic if you plan to use the car with motor removed.
Clean the Motor Thoroughly using Diesel and toothbrush. Its not recommended to use water for cleaning.
Step 4: Motor Electrical Contact Checking & Test
Check functioning of motor using simple methods as shown in Images. If the motor spins, Hopes are very good.
Step 5: Motor Servicing
Lubricate the motor worm and Geared shafts with Pink bearing grease
before Refit. Also Apply liberal RTV sealant on Parts where wires are exiting the sensors or motor casings. This should prevent Further problems with Moisture.
Step 6: Preventive Maintainance and Paint
The motor and Motor Guard plate was then painted with regular spay Paint. A light Sanding helps before paint to help it stick. Painting will prevent future rusting and extend part life.
Step 7: Finally Done.
Shift the vehicle into 4x4 and go on that lovely trail you've been waiting for!