Clearing the OBD?

[DJ Menasco]

Does anyone know if you have to reset the on-board diagnostic display after it throws a code? I had a 48 pop up indicating the stepper motor was on its way out, which was logical seeing how the D90 was stalling when I rolled to a stop. I replaced the motor based on this diagnosis and the stalling issue was resolved.

However, the code 48 popped up again along with the “Check Engine” light despite disconnecting the battery after installing the new stepper motor. I assumed this would clear the code & shut the Check-Engine light, but it popped up again. I guess I could clear the display following this SOP (http://www.fourfold.org/LR_FAQ/Defender/FAQ.Engines.Fault.Codes.html), but outside performing this has anyone else had to reset their system after a code has been thrown? Thanks for any help.

DJ

[Mike Hippert]

If it keeps happening you may have a loose wire on the stepper or something, I have always been able to reset my ECM by disconnecting the battery for 5 min or so.

[m.michaels]

I always thought the ECU had a non-volatile memory - meaning even if I unplug the battery the fault code is still retained. I thought on the '94 it would work because it had a volatile memory (at least I thought it would clear on my soft-top at the time). On my '97 the codes are retained - at least I haven't been able to get rid of them with the battery disconnected trick - maybe that is the problem on the '95. I thought I rememberd that the code would be reatined and would eventually reset itself with so many "OK" starts. Or you could go to the dealership or local mechanic and have them do it straight away . . .

[thelandroverguy]

I went down to my local parts store. (Kragen) I used thier OBDII reader and read my code then cleared it.

[Mike Hippert]

Well the 97 ECM is different as it is an OBD2 system and the 93s, 94s, and 95s had OBD1 systems.

[DJ Menasco]

Found this in the FAQ.

I recently had to reset both of these (Check Eng. and Service Eng.) lights on my 94 RR.

The service engine light is simply reset by inserting a suitable prod into the hole. Its posiible that you need something more substantial than a paper clip. It didn't work for me the first time so I resorted to using a small philips screw driver that did the trick.

The Check Engine light can be reset (assuming you have fixed the problem that caused it to illuminate in the first place) by disconnecting the lead from the display unit while the ignition is switched on. There is a 5 pin (or so) connector in the lead from the display. Then switch the ignition off and wait for the main relay to drop out. Recoonect the lead and evrytjing should be fine. Of course this didn't work for me either so what I did was disconnect the battery for about 30 seconds while the lead was disconnected and that fixed it.

Good Luck
Mike

[owen]

Just returned from a five day expedition in the mountains where the Check Engine light came on with code 48. Everything ran well even with th light on - until at home I reset the OBD to see if there were any other codes. The OBD display cleared - BUT when starting the engine it sputtered, died and refused to run.

Tried the battery disconnect reset. First attempt at starting showed the usual code 2 for the disconnect then blank on second starting attempt. Refused to even sputter.

No modifications or engine bay work has been done except for replacing the air filter and topping off the steering fluid.

Would really appreciate some guidance on getting her going...

Thanks in advance,

Owen

[Hans]

Just returned from a five day expedition in the mountains where the Check Engine light came on with code 48. Everything ran well even with th light on - until at home I reset the OBD to see if there were any other codes. The OBD display cleared - BUT when starting the engine it sputtered, died and refused to run.

Tried the battery disconnect reset. First attempt at starting showed the usual code 2 for the disconnect then blank on second starting attempt. Refused to even sputter.

No modifications or engine bay work has been done except for replacing the air filter and topping off the steering fluid.

Would really appreciate some guidance on getting her going...

Thanks in advance,

Owen

Well, let's start with the basics.

When you go to start it, does the starter crank the engine, and it just doesn't catch?
Or does nothing happen when you turn the key?

Sputtering on startup usually means a lack of fuel. When you turn the key from OFF to ON (but not to START), do you hear a buzzing from the fuel tank area from the pump priming?

-Hans

[owen]

Well, let's start with the basics.

When you go to start it, does the starter crank the engine, and it just doesn't catch?
Or does nothing happen when you turn the key?

Sputtering on startup usually means a lack of fuel. When you turn the key from OFF to ON (but not to START), do you hear a buzzing from the fuel tank area from the pump priming?

-Hans
Hi Hans thanks for responding!

1) Starter cranks engine when key is turned.
2) No Buzzing from fuel tank area when ignition is ON (but not to START).

Hmmm. Along those lines:
There is no strong fuel smell from exhaust after cranking. Also, for last few weeks engine has on occasion 'hiccupped' once after 5mins running (when it reaches temperature). Truck is facing uphill presently.

Also I have (low pressure) powerwashed the underside


Owen

[Hans]

no buzzing? then sounds like fuel pump isn't running, as you should be hearing it for a couple seconds pressurizing the system. I'd start with checking the fuse for it, hopefully you didn't pop a wire off when pressurewashing.

-Hans

[owen]

no buzzing? then sounds like fuel pump isn't running, as you should be hearing it for a couple seconds pressurizing the system. I'd start with checking the fuse for it, hopefully you didn't pop a wire off when pressurewashing.

-Hans
Thanks Hans. The fuel pump fuse checked out ok so it must be a bad connection or the pump is suddenly shot. Can the pump connection be checked easily without drpopping the tank?

If its not that could it be the OBD or computer?

-Owen

[d901560]

Check the fuel pump relay before dropping the tank. The fuel pump relay also powers the o2 sensors which can trigger the check engine light as it goes out.

[owen]

Check the fuel pump relay before dropping the tank. The fuel pump relay also powers the o2 sensors which can trigger the check engine light as it goes out.

Great tip. I was just about to drain and drop the full tank!
Where can I find the relay and whats the easiest way to check it?

The engine check code was 48 before all this happened.

Owen

[owen]

She's running! Twas the powerwash of her private parts that violated her. Took three days to dry out the Fuel pump connections in dry Colorado air.

Now how does that work for deep water...

Thanks for your suggestions

Owen