The right tool for the job

 

So we had to deal with a non turbo with an ABS fault, the system is essentially the same as the one fitted to the twin turbo so any fault finding is the same which ever model you have.

 

The ABS system fitted to the zed has a very easy to use built in diagnosis so there is often no need for any specialist equipment. The self diagnoses is built into the abs ecu module and the ecu has a small led that flashes a set number of times to correspond to a particular fault code that is stored within the unit.

 

 

 

 

A small drive is all that is required until the ABS warring light comes on and stays on, by pulling over and leaving the car running the latest fault codes can be read, the codes are limited to a maximum of 10 separate codes but then the system is relatively low tech, incidentally the most common fault by far is one of the front wheel sensors

 

A.B.S. Fault Codes No. of Flashes Faulty

 

1 Left Front Actuator Solenoid Circuit

2 Right Front Actuator Solenoid Circuit

3 or 4 Rear Actuator Solenoid Circuit

5 Left Front Wheel Sensor Circuit

6 Right Front Wheel Sensor Circuit

7 or 8 Rear Wheel Sensor Circuit

9 Motor and Motor Relay

10 Solenoid Valve Relay

16 or Continuous Control Unit

Dash Warning but L.E.D. Off Control Unit Power or Ground

 

 

So back to the non turbo zed in question, the ABS light was on when the ignition was first tuned on and went through the normal and correct pattern of going out after the engine was started.

Moving off the light came back on almost immediately which is unusual in as far as the system does not operate under 20 mph approx. so the warning light coming on so quickly was not normal at all.

 

Initially we went for the obvious and did a built in diagnostic code check, the led light was flashing 9 times, fault 9 relates to “ pump relay contact” so it made sense to change the relay.

 

 

So following the change of relay a quick test drive revealed the fault was still present , so all the fuse were checked again, the two in the small fuse panel by the brake master cylinder and one in the fuse box by the n/s headlight, all were ok.

 

 

 

As an eliminator the ABS ecu was changed for a know good one, however the fault remained, the cables at the abs unit in the boot were checked next for condition and supply etc.

 

 

 

 

 

With no more to go on it was time to bring the big guns out, well a genuine Nissan 300zx ABS test unit from 1990 no less.

 

 

 

The unit requires the abs ecu to be unplugged and the unit takes the place of the ecu, from here all circuits can be check in a matter of minutes.

 

 

All of the wheel sensors passed with flying colours both on resistive value and pulse output, the ecu had been changed and the fuses all were in good order and supplying power.

 

 

 

Continue on next thread

Edited August 22, 201114 yr by JeffTT

Continued...

 

The Nissan tester unit has a series of tests you need to do in a specific order and during this a failure was detected with the pump relay, remember the original self diagnostic check said the same, this had been changed so could not be that.

 

The Nissan tester goes a bit further though than the built in test in that abs pump can be activated from the tester but it was not responding and the display screen showed an inverted voltage across the relay contacts, the pump was disconnected electrically from the relay base and a temporary supply direct to the pump and it ran perfectly

 

Back to the fuses and all good and supplying 12v+ to the outputs of the fuses, strange, with the pump relay removed and the ignition on the relay base contacts were checked and there appeared to be a missing live supply on the pump supply.

 

 

 

So then it came clear a cable fault between the relay base supply fuse and the relay base existed, with a few zillion miles of cable loom to unravel it seemed more prudent to just run a new supply from the original fuse location to the pump.

 

 

 

 

 

 

By running the cable through to the original fuse location we could use the original circuit breaker and so looked original and would be a long term repair, the only issue here is the fuse box cables are only accessible from below it and the supply loom is very short, by undoing the fuse box fixings and rotating it the lower cover can be removed to splice in the new cable.

 

 

 

 

 

Once the cable was run from the fuse box to the loom at the boot abs unit a secure connection could be made there, as can be seen below, the red cable with the blue connector

 

 

So a final test drive and the abs was all working perfectly again, there is no doubt the fault would have been found with out the Nissan ABS tester but as the title of the thread it really helps when you have the right tools even just as a back up.

 

Jeff TT

Edited August 22, 201114 yr by JeffTT

Nice read Jeff:thumbup1:

Nice read Jeff:thumbup1:

 

Your welcome. :D

 

Jeff

Nice one Jeff!

its like a zed university on here when Jeff posts one of these how to with pics..really good stuff Jeff and very usefull to all members ...nice one mate

Top job as aways jeff :biggrin:

Awesome stuff... where the hell did you manage to get that genuine nissan abs tested from?! I'd be amazed if there is a main dealer that still has one of those!

Awesome stuff... where the hell did you manage to get that genuine nissan abs tested from?! I'd be amazed if there is a main dealer that still has one of those!

 

From a Nissan dealership closing down, was unused when I got it.

 

Jeff TT

it looks really dated dosnt it :lol:

it looks really dated dosnt it :lol:

 

Yeh proper old school, in fact reminds me of something from my schooldays in physics class.

 

Jeff

LOL! we still have a Mercedes ABS tester for vehicles from the 80's (124's, 201's, 126's) - looks even more outdated than that!! :D

Yeh proper old school, in fact reminds me of something from my schooldays in physics class.

 

Jeff

 

Or somthing off the 1st space shuttle :clown:

or the first series of star trek .............usualy held by the geezer bit part actor in the red shirt, the one that always got killed in every episode....

I love Jeff's Tech threads, they are so detailed and the infomation in them is priceless. Keep them comming Jeff, Top Job. :thumbup: