My 2002 Suzuki GV with the Peugeot RHZ engine(DW10ATED) and Bosch electronics which has done only 225000 miles has started going into occasional limp mode. When it does it usually throws a P0903 fault code and usually after about 5 miles.
This ODB2 P0903 code implies that the clutch actuator is reading high. I guess they mean high resistance/impedance i.e.open circuit.
However, given that it is a manual gearbox, without cruise control and there is no clutch switch near the pedal and nothing on the clutch hydraulic line this seems to be an impossible fault.
I've looked at a few web sites and discovered that I am not alone. A (very) few others have had the P0903 code on Pugs but no solutions. Nobody seems to have any explanation: unsurprising really as it would seem to be a nonsense code.
It is definitely P0903 - I've just rechecked with a second scanner. What is odd is that for a week about a month ago it was occasionally taking ages to start and would throw a P0230 fault. Normally that would mean the lifter pump was faulty, but it was replaced less than 20,000 miles ago and I can hear it humming away quite contentedlyat switch on. Also fuel was and is flowing happily at pressure through the filter. The pump relay and the fuel filter including housing were all replaced at the the same time as the pump - all OEM (Bosch) bits. The P0230 fault of a month ago cleared when I refilled with fresh diesel and I had more or less convinced myself that it was a bad tank of diesel that had caused it. It was about 2 weeks after that that the P0903 started. I reckon a leak off test might be next although as the car runs superbly for 5-10 miles before the fault appears an injector problem seems unlikely. It also suggests the hp pump and rail are fine, I'd have expected 'proper' injector faults to show up if the problem was there. If injectors are OK I'll check the hp regulator. It is a bit tricky to get at though. The only thing that seems to correspond to the fault is that the engine reaches operating temperature around about the same time and I noticed one report of someone with a Peugeot finding a P0903 fault alongside a temperature sensor fault - however in that instance there was a temperature sensor fault. Temperature gauge on mine is fine. I've heard that MAF's can have odd side effects on the HDI. I've occasionally had a P0243 fault (Wastegate solenoid) although there is nothing wrong with the solenoid - or wastegate or turbo for that matter. This tends to happen on really hot days and as others have suggested that the fault is actually due to the MAF misreading pressures.
I am still bewildered. The ecu's on these are pretty primitive. The Furby is much more sophisticated! . Someone somewhere must have access to the code or at least a flowchart. Help
Oops..I didn't mean MAF pressure in thta last post - I meant flow. Apparently the P0243 fault can appear if the ecu doesn't detect a drop in airflow shortly after the wastegate opens, For some obscure reason the ecu flags this a s a solenoid fault. A solenoid fault is a possibility but it could be caused by other things such as a faulty MAF or stuck wastegate actuator. I can't see how that could register a p0903 fault on a non existent clucth switch/actuator though.
Yes it is hydraulic. I replaced the clutch about 35,000 miles ago and it is a normal standard clutch, no dual mass flywheels or anything like that. Fault re-appeared today after going like a dream for about 70 miles at 70 mph. .I had just topped up with diesel (Shell V-power). It feels like fuel starvation and I can now tell it is about to happen because the engine is not as responsive as it should be. It feels as if it already was in limp mode a few minutes before the mil light comes on.
Blimey. I've found (I think) the problem and the solution. The brake switch on the Grand Vitara is a Single Pole Double Throw (SPDT) type and one pole is connected to the stop lights. But the other is connected to the ecu to signal when the brakes are applied . However it is connected using the clutch switch logic circuit. This means that when the brakes are applied the ecu detects this and the fuel is reduced. If the switch is faulty (or as it seems to have been in my case, even just a bit loose) the ecu receives a signal that the brakes have been applied when they haven't.
I reckon it is pretty irresponsible for Peugeout/Bosch to have allowed their designers to allow the brake pedal switch to masquerade as a clutch switch. I think Suzuki should have spotted it as well even though the car uses the PSA Peugeot 'plug'n'play HDI engine and ancilliary equipment from Bosch.
Anyway, I removed the switch which felt a bit loose, had a look at the insides which were pristine, and put it back. it is now much tighter than it was. The P0903 fault hasn't been seen since.
So if you have a 2.0 HDI with P0903 fault - before anything else check the brake pedal switch.
Aargh ignore previous post. This hasn't solved the P0903 problem - a week later it has re-emerged. Also this time I took the switch off and examined the cable and disciovered that the brake swict has only 2 wires - no extra pair going to the ecu (although the Puegeot RHZ circuit diagram shows them).
It could be that the stop light wire itself goesto the ecu - that would work, but I am beginning to suspect it must be something else.
Also the P0243 fault - absent for months - re-appeared a little while later.
hi did this fault ever come back as i have a 406 with exactly the same faults and im banging my head now spent hours with readers and multi meters and no sucess
look forward to your reply
Sorry for slow reply - the faultb never returned so I didn't look at the site again. However a different fault arose last month when the car wouldn't start. It turned out that the plug/socket connecting to the fuel regulator (on the back of the hp pump) had worked itself looseand it did it again a week later. Weather is too cold to get at it and fix properly at the moment so I've used a couple of plastic ties to hold in position. When it happened the second time it threw a P0230 fault - rather misleading as this suggests a lifter pump fault.. If you are still getting the P0903 fault check both that the brake switch is tight AND that the pug/socket to the fuel regulator is tight. I've heard that the fuel regulators on these can be a problem as well - they used to be extortionately expensive but I have seen aftermarket ones (I think an Italian make) for sale recently at £65 or so. If the problem persists on my car I think I may invest in one of these.