Useful links:

Only registered users can see links on this forum! Register or Login on forum!

(replace instances of "CEL" with "4WS" )



4WS Error Codes

Thanks to JohnnyB and Confused

Code:

Code    System                        Point                  Terminals        Affected No code  -                             -                     7&23             CU, HC No code  -                             -                     18,25,4,2,16&24  CU, HC, A 10      Sub Steering Angle Sensor     Front                  22,26            CU, FSSAS, HC 11      Sub Steering Angle Sensor     Rear                   29,17            CU, RSSAS, HC 12      Sub Steering Angle Sensor     Front                  26,21            CU, FSSAS, HC 13      Sub Steering Angle Sensor     Rear                   17,28            CU, RSSAS, HC 14      Sub Steering Angle Sensor     Front                   -               CU - Replace 4WS Control Unit 15      Sub Steering Angle Sensor     Rear                    -               CU - Replace 4WS Control Unit 16      Sub Steering Angle Sensor     Front                  22,26,21         CU, FFSAS, HC 17      Sub Steering Angle Sensor     Rear                   29,17,28         CU, RSSAS, HC 18      Sub Steering Angle Sensor      -                      -               CU - Replace 4WS Control Unit 20      Main Steering Angle Sensor    Front                  8,15             CU, FSSAS, FMSAS, HC 21      Main Steering Angle Sensor    Rear                   6,13             CU, RSSAS, RMSAS, HC 22      Main Steering Angle Sensor    Front                  8,15             CU, FSSAS, FMSAS, HC 23      Main Steering Angle Sensor    Rear                   6,13             CU, RSSAS, RMSAS, HC 24      Main Steering Angle Sensor    Front                  8,15             CU, FSSAS, FMSAS, HC 25      Main Steering Angle Sensor    Rear                   6,13             CU, RSSAS, RMSAS, HC 26      Main Steering Angle Sensor    Front                   -               CU - Replace 4WS Control Unit 27      Main Steering Angle Sensor    Rear                    -               CU - Replace 4WS Control Unit 28      Main Steering Angle Sensor    Front                  12               CU, FSSAS, FMSAS, HC 29      Main Steering Angle Sensor    Rear                   20               CU, RSSAS, RMSAS, HC 30      Wheel Speed                   Front                  19               CU, FWSS, HC 31      Wheel Speed                   Rear L                 3                CU, RLWSS, ABSCU, HC 32      Wheel Speed                   Rear R                 1                CU, RRWSS, ABSCU, HC 33      Wheel Speed                   Rear RorL              3,1              CU, ABSCU, HC 34      Wheel Speed                   Front                  19               CU, FWSS, HC 35      Wheel Speed                   Rear L                 3                CU, RLWSS, ABSCU 36      Wheel Speed                   Rear R                 1                CU, RRWSS, ABSCU, HC 37      Wheel Speed                   Rear L                  -               CU - Replace 4WS Control Unit 38      Wheel Speed                   Vehicle Speed           -               CU - Replace 4WS Control Unit 40      4WS Control Unit              4WS Control Unit        -               CU - Replace 4WS Control Unit 41      4WS Control Unit              4WS Control Unit        -               CU - Replace 4WS Control Unit 42      4WS Control Unit              4WS Control Unit        -               CU - Replace 4WS Control Unit 43      4WS Control Unit              4WS Control Unit        -               CU - Replace 4WS Control Unit 44      4WS Control Unit              4WS Control Unit        -               CU - Replace 4WS Control Unit 45      4WS Control Unit              4WS Control Unit        -               CU - Replace 4WS Control Unit 46      4WS Control Unit              4WS Control Unit        -               CU - Replace 4WS Control Unit 50      Control Logic                 Motor Lock             C+,D-            CU, RAM, HC 51      Control Logic                 Wheel Caught In Ditch  C+,D-            CU, RAM, HC 60      Power Unit                    Motor                  C+&D-,33+&34-    CU, RAM, PSH, HC 61      Power Unit                     -                     C+&D-            CU, RAM, PSH, HC 62      Power Unit                    Motor                  33+&34-          CU, RAM, PSH, HC 63      Power Unit                     -                      -               CU, RAM, PSH, HC 64      Power Unit                    4WS Control Unit        -               CU - Replace 4WS Control Unit 65      Power Unit                    4WS Control Unit        -               CU - Replace 4WS Control Unit 70      Temporary Driving Conditions   -                     25               CU, HC - Check Symptoms / Conditions 71      Temporary Driving Conditions   -                      -               CU - Check Symptoms / Conditions 72      Temporary Driving Conditions   -                     4                CU, HC - Check Symptoms / Conditions 73      Temporary Driving Conditions   -                      -               CU, A - Check Symptoms / Conditions 74      Temporary Driving Conditions   -                     14               CU, PB, HC - Check Symptoms / Conditions       Key:       FSSAS - Front Sub Steering Angle Sensor       RSSAS - Rear Sub Steering Angle Sensor       FMSAS - Front Main Steering Angle Sensor       RMSAS - Rear Main Steering Angle Sensor       FWSS  - Front Wheel Speed Sensor       RLWSS - Rear Left Wheel Speed Sensor       RRWSS - Rear Right Wheel Speed Sensor       ABSCU - ABS Control Unit       CU    - 4WS Control Unit       RAM   - Rear Actuator Motor       PSH   - Power System Harness       A     - Alternator       PB    - Parking Brake       HC    - Harness Connector

Credit goes to JohnnyB who actually took this information out of the service manual originally, I've just tidied it up and put it into tabular form!

Thanks Garry, great job!

4WS ECU Removal

Thanks to Tron

Removing the back seat to get at it is a doddle, and yes you do have to remove it. You also have to remove the boot trim as the unit goes backwards through the boot. IIRC the bolts that hold the unit in place in its bracket are behind the passenger side rear seat.

DISCONNECT THE CAR BATTERY!!! (some of the wires on the ecu are still live without the ignition on, I found out during my arch welding experience

To remove the seats (easiest bit IMO)
1) remove the base of the passenger rear seat, theres two black clips below the seat cushion, one on either side at the front of the cushion, pull these clips towards the front of the car, you might have to press down on the cushion to move them.
2) lift the lower cushion away at the front and pivot it down at the back, you should see a bracket at the back of the lower cushion that holds it behind the backrest, just pivot it down it'll come free.
3) theres two 10mm bolts at the bottom of the beckrest, they sit in two loops of metal, one each side, unbolt these.
4) lift the seat back directly upwards to remove it from the clips at the top of the cushion. Job done.

I suggest you the remove the interior trim out of the boot before going further, thats held on by two plastic trim clips, one in the centre of the 4ws ecu bracket, and the other near the hatch opening(other seat back). It might be advisable to remove the rubber trim/seal from around the hatch to get the panel out, it (the rubber trim) just pulls off and pushes back on. With the boot open you'll be able to see more of the back of the unit.

Next unclip the plastic cover that covers the black, brown, red and white connectors down the left hand side of the unit. If you have a camera I suggest you take a picture of their locations, although they should only fit in a certain order, best to be safe. Undo the 10mm nuts holding those wires in place.

Then unclip the three bottom connectors from the unit if you can, else just proceed undoing the mount bolts for the ecu bracket(not the ones which hold the ecu to the bracket), you have to remove the bracket aswell to get the ecu out. The silver metal bracket should fit round the ecu from inside the boot and mount to another silver bracket/plate, you shouldn't have to remove any bolts from the bodywork of the car.

Then with the unit out perform the fix, and refit in reverse. This is all from memory over 2 years ago, so don't shoot me if I'm wrong

HTH
Paul

Reset 4WS

(Thanks to Taffylude)

1. Apply the hand brake.
2. Short the service connector pins with a paper clip or something similar.
3. Turn the steering wheel to CLOCKWISE (right) 45-65 degrees and hold it that way.
4. Turn the ignition switch to II (on) position but DON'T start your engine.
You'll see that all your warning lights will go on and off, don't pay attention to them.
5. After your 4WS light goes OFF, turn the steering wheel to CENTRE (turn it left) position within 4 seconds and hold it still.
6. When your 4WS light turns ON, turn your steering wheel CLOCKWISE again to 45-60 degrees and hold still (again within 4 seconds).
7. When the 4WS light goes OFF, turn the wheel to the centre position again within 4 seconds and hold it still.
8. If your 4WS light blinks TWICE then you succeeded.
If it stays on after this that means you failed, so simply turn the ignition off and go back to step one and try again. The tricky part with this procedure is that you should do all the steering inputs within 4 seconds so keep it in mind.
If you succeeded, turn your ignition off, remove the short on the service connector, start your engine and check if it's working.
This may look complicated but it is very easy, it only takes a few minutes.

Thanks to Taffylude.

**EDIT**

It has been reported by a few members that this procedure only works on the 5th Gen Prelude. To reset the 4WS on the 4th Gen, a simply disconnection of the battery seems to work.

4WS Alignment

A number of places claim to carry out 4 wheel alignment, but few actually can for a car equiped with 4WS.
For those places that do it properly, a locking key should be used to physically lock the rear wheels in place during the alignment. The key is availalbe at only a handful of Honda dealerships across the UK, and many dealerships do not even know about it.

If you wish to make your own, then here is a drawing of the tool which was very kindly supplied & drawn up by JohnnyB .

4WS Removal & Conversion to 2WS

Thanks to dohc-vtec

Only registered users can see links on this forum! Register or Login on forum!

The importance of using Genuine Honda power steering fluid and the problems/differences it can make, including poor or unevenly weighted steering.

Thanks Masta Cutz.

Only registered users can see links on this forum! Register or Login on forum!

Power steering fluid change - "how to"

Thanks Pushki77

Only registered users can see links on this forum! Register or Login on forum!

Re-soldering the 4WS computer

Thanks to adamwilkes


One frequent problem with the 4WS seems to be fatigue/cracks in soldered joints inside the 4WS control box (behind the passenger rear seat). This is fixable and the fix stops intermittent failures of the 4WS to set up correctly from startup - 4WS orange light failing to go out.

The LH rear seat base is removed (2 x pull-clips under the front edge); the seat back is unbolted; the boot liner on the LHS pulled/unclipped; the control box unwired (DISCONNECT BATTERY FIRST!!) - making a note of where the heavy coloured wires go; unbolt the control box and steel cover plates (bolts all over the place - look carefully!).

On a soft bench, unscrew the lid of the control box - beware of the ribbon connector which must not be yanked - support the lid on a big book/box; undo the screws that hold down the circuit board with the copper strips going to them (lots of screws, including those through the row of transistors, and some of the copper connections - feel your way!); the culprits are the smallish black boxes (relays) - the soldered connections on the underside of the circuit board crack (sometimes invisibly) and need resoldering. Resolder them all - maybe 10 joints.

I have also found that some of the capacitors on the other circuit board in there have begun to swell/burst, which is a well-known problem in electronics generally. My 10uF 35volt capicitors had swollen. Replace as required!
Reassemble with care and slow checking - your 4WS should now work 100%.