QuestionHow do I rectify the stalling of my freelander
and correct the engine light and hill descent from coming on all the time
AnswerHi Ivan,
you should find someone who can read the OBDII codes that are associated with this problem. It should lead you to the possible components involved. Advance Auto and a couple of other national auto parts shops offer a free service. Local mechanics will also do this but they'll charge you for it. Then there is the dealer.
Is it possible that HDC is causing your engine stalling? Based on what you have written, perhaps its a component of the ECM, namely, the APP (accelerator pedal potentiometer). It is a crucial part of the EMS (engine management system) with the EMS having various other sensors that are used to maintain the engine at optimal levels.
From the Freelander workshop manual:
EMS Sensors
The EMS incorporates the following sensors:
An APP sensor.
Crankshaft Position (CKP) sensor.
Camshaft Position (CMP) sensor.
Mass Air Flow (MAF) sensor.
An Intake Air Temperature (IAT) sensor.
An Engine Coolant Temperature (ECT) sensor.
Thermostat monitoring sensor.
Four Heated Oxygen Sensors (HO2S).
Two knock sensors.
Here is what the LR Freelander workshop manaul has to say:
<<begin>>
The APP sensor enables the ECM to determine the throttle position requested by the driver on the accelerator pedal.
The APP sensor is installed on the pedal box and consists of a twin track potentiometer with wipers driven by a linkage connected to the accelerator pedal. Each potentiometer track has a 5 volt supply and ground connection from the ECM, and produces a linear signal voltage to the ECM proportional to the position of the accelerator pedal.
The signal voltage from track 1 of the potentiometer is approximately double that of the signal voltage from track 2. From
the sensor signals, the ECM determines driver demand as a percentage of pedal travel, where 0% is with the pedal released and 100% is with the pedal fully depressed. Driver demand is then used to calculate throttle angle, fuel quantity and ignition timing.
<<NOTE THIS>>
The ECM also outputs driver demand on the CAN system, for use by the brake and gearbox control systems.
The ECM stores the signal values that correspond with closed and wide open throttle, and adapts to new values to accommodate component wear or replacement.
The signals from the APP sensor are monitored by the ECM for short and open circuits and plausibility. If a fault is detected, the ECM:
Stores a related fault code in memory.
Illuminates the SERVICE ENGINE warning lamp in the instrument pack.
Inhibits the driver demand message on the CAN bus, which disables the Hill Descent Control (HDC) function of the ABS modulator and reduces the performance of the automatic gearbox (harsh gear changes and loss of kickdown).
Adopts a throttle limp home mode.
The throttle limp home mode adopted depends on the nature of the fault:
If a fault is detected with one potentiometer track, the ECM limits vehicle acceleration by limiting throttle plate opening.
If a fault is detected with both potentiometer tracks, the ECM uses the throttle plate to run the engine at a fixed speed of 1472 rev/min while the brake pedal is released, and idle speed
(750 rev/min) while the brake pedal is pressed or if there is a brake pedal sensor fault.
If there is a process fault in the ECM, the ECM either uses fuel injection cut-off to limit engine speed to 1300 rev/min or disables
fuel injection to stop the engine.
<<End>>
SO... it could be a problem with an sensor OR (worse case) it could be the ECM itself (ouch! $$$$)
Let's hope its something less expensive. I would find an independent LR mechanic who would be willing to test swap some sensors to determine the real cause. I doubt a LR dealer would do this as it is not profitable enough.
Best of luck,
JohnMc
PS. I use www.car-part.com for salvaged parts. Sometimes I luck out and get a nearly new sensor for a fraction of the dealer price. Just thought I'd add this as a possible option.
