Land Rover Repair: T027 Code showing up per mechanic, air control valve, camshaft sensor

Question
My mechanice says the code T027 (or maybe TO27) is showing up for the problem we are having with our 1996 Land Rover Range Rover but he can't find anything on that code. Can you tell me what this means? The Rover is dying when the RPM's are not keep up so anytime the idle is low (stopping etc).
Thanks for your help.

Answer
Hi Ginger,

I'm not sure what that code is - T027.  DTC's are usually are in the format of P#### or similar.  GM has a T027 but its OBDI and related to the ABS.

There is a P0207 code:  Injector 7 Circuit Fault.

Idle problems can be tricky, in your case it could be idle control valve.

" Idle air control valve (common):
The idle air control valve is screwed into a housing attached to the rear of the plenum chamber, between the plenum chamber and bulkhead. The idle air control valve has two windings which enable the motor to be energised in both directions thus opening or closing the air valve as required by the ECM.  The idle air control valve will open and allow extra air into the plenum chamber to maintain engine idle speed when the engine is under increased (Electrical
and Mechanical) loads. The idle air control valve will control engine idle speed when the vehicle is stationary. "

Could also be Camshalf position sensor (possibly if code P0207):

"Camshaft position sensor (CMP Sensor):
The camshaft position sensor is located in the engine front cover. It produces one pulse every two revolutions. The signal is used in two areas, injector timing corrections for fully sequential fuelling and active knock control.  If the camshaft sensor fails, default operation is to continue normal ignition timing. The fuel injectors will be actuated sequentially, timing the injection with respect to top dead centre. Injection will either be correct or one revolution out of synchronisation. The fault is not easily detected by the driver. The fault is
indicated by illumination of the malfunction indicator light (MIL) on North American specification vehicles. "

And it could also be the Throttle position sensor (very common):

"Throttle position sensor (TP Sensor):
The throttle position sensor is mounted on the plenum chamber and connected directly to the throttle shaft.  The sensor is a variable resistor, the signal from which (0 - 5V) informs the ECM of the actual position of the throttle disc. As there is no default strategy, failure of the sensor will result in poor idle and lack of throttle response. If failure occurs in the closed
position the engine will only reach 1750 rev/min when the ECM will initiate overrun fuel cut off. The fault is indicated by illumination of the malfunction indicator light (MIL) on North American specification vehicles. "

It's rare to see injector failures but I won't discount that from happening.  

Hope this is helpful,

JohnMc