hi guys first post here, hopefully someone can help me get to the bottom of this issue, i have posted this also on another range rover forum and so far no one has had any ideas. after a week of trawling the internet and various tests i'm still getting engine failsafe mode followed a few seconds later by hdc/air suspension inactive, brake warning light, abs warning light and occasionally the engine check light, also accompanied by error code po120 & po221 (throttle potenometer 1 &2) and occasionally throttle stop lower learn, i clear these codes and they come back within seconds even if the car is not running. it's a 2003 l322 with bmw m62 4.4 v8 engine, issues exsist on petrol & lpg, so far i ahve done the following:
changed accelerator pedal (twice) both used units but rule of thumb both shouldn't be faulty
checked all the wires from throttle body to ecu every one has .1 ohm resistance
checked thermostat this has proved to be ok with no sign of overheating on the plug
tried a different throttle body today but as this is a used unit from a breaker probably untested so could be faulty
checked the blue ground wire from the throttle body to earth through the ecu, .1 ohm resisitance
checked battery after car been stood for 8 hours it's showing 12.5v
checked the alternator, my local alternator centre say it's ok, it's pushing out 14-14.1v at tickover and i don't see the battery light come on with everything running, i retested it today headlights on main beam, air con on, heater blower full and it was showing just over 16 volts, but went back to 14 once everything was off.
this morning checked wires to accelerator pedal with multi meter i have 5v in on 2 pins, ground on 2 pins meaning the other 2 pins must be signal back to ecu
if i press the accelerator pedal there is a slight hesitation before the car revs, followed by a drop in revs before it picks up and ticks over normally. but throttle body opens and closes normally with pedal movement.
hdc/ air susp inactive etc usually trigger after engine failsafe and i hit approx 30mph
i checked the actuators operation at tick over with hawkeye and idle valve/ actuator shows active for a second then switches to inactive not sure if this is correct?
i have also noticed a couple of times when it triggers with ignition on but engine not running, it trys to close the throttle butterfly a little further than it is sitting normally, then just releases it, not sure if this is normal.
apart from this issue car drives normally and is not down on power i don't want to buy a throttle body if it's not the issue, especially at £316 plus vat, although bmw have just quoted me £204 plus vat
most of the bmw sites report loss of power with engine failsafe mode i'm not experiancing any loss of power
live data taken with hawkeye
error codes p0120 & p0221
Throttle potentiometer 2
Throttle potentionometer
Live data
Eng speed fluctuates from 576-630
Eng spec speed 600
Coolant temp 95c
Rad cool temp 52c
Intake air temp 43c
Air mass 18.9-19.2 kg/h
Timing 189.5 kW
Inj time 3.8 ms
Throttle pos 1%
Battery 13.8 volts
Throttle pot1 .59v. Ful throttle 4.36
Throttle pot2 1.53v full throttle .37 volt
Pedal trav sens 1 .33v full throttle 2.31v
Pedal trav sens 2 .65v full throttle 4.66v
changed accelerator pedal (twice) both used units but rule of thumb both shouldn't be faulty
checked all the wires from throttle body to ecu every one has .1 ohm resistance
checked thermostat this has proved to be ok with no sign of overheating on the plug
tried a different throttle body today but as this is a used unit from a breaker probably untested so could be faulty
checked the blue ground wire from the throttle body to earth through the ecu, .1 ohm resisitance
checked battery after car been stood for 8 hours it's showing 12.5v
checked the alternator, my local alternator centre say it's ok, it's pushing out 14-14.1v at tickover and i don't see the battery light come on with everything running, i retested it today headlights on main beam, air con on, heater blower full and it was showing just over 16 volts, but went back to 14 once everything was off.
this morning checked wires to accelerator pedal with multi meter i have 5v in on 2 pins, ground on 2 pins meaning the other 2 pins must be signal back to ecu
if i press the accelerator pedal there is a slight hesitation before the car revs, followed by a drop in revs before it picks up and ticks over normally. but throttle body opens and closes normally with pedal movement.
hdc/ air susp inactive etc usually trigger after engine failsafe and i hit approx 30mph
i checked the actuators operation at tick over with hawkeye and idle valve/ actuator shows active for a second then switches to inactive not sure if this is correct?
i have also noticed a couple of times when it triggers with ignition on but engine not running, it trys to close the throttle butterfly a little further than it is sitting normally, then just releases it, not sure if this is normal.
apart from this issue car drives normally and is not down on power i don't want to buy a throttle body if it's not the issue, especially at £316 plus vat, although bmw have just quoted me £204 plus vat
most of the bmw sites report loss of power with engine failsafe mode i'm not experiancing any loss of power
live data taken with hawkeye
error codes p0120 & p0221
Throttle potentiometer 2
Throttle potentionometer
Live data
Eng speed fluctuates from 576-630
Eng spec speed 600
Coolant temp 95c
Rad cool temp 52c
Intake air temp 43c
Air mass 18.9-19.2 kg/h
Timing 189.5 kW
Inj time 3.8 ms
Throttle pos 1%
Battery 13.8 volts
Throttle pot1 .59v. Ful throttle 4.36
Throttle pot2 1.53v full throttle .37 volt
Pedal trav sens 1 .33v full throttle 2.31v
Pedal trav sens 2 .65v full throttle 4.66v
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