14.

10 Rover MEMS - MPi/SPi

EOH1417
20 Throttle switch (TS)
8 9 33 30 16

e'arth 1 On pre-1993 models equipped with the

throttle pedal.-mounted 'idle switch', the
engine will gasp, die and fail to respond
properly if the engine speed is increased by
moving the throttle lever directly from under
the bonnet. This is because the ECM links the
KS TPS CTS ATS idle switch closed condition with rpm, and
enters fuel deceleration cut-off mode. The
14.10 Typical local wiring diagram: engine rpm should only be increased by use
sensors of the accelerator pedal from inside the car.
2 However, during testing it is sometimes
2 Voltage to the injectors is provided from more convenient to be able to control the
either.the system relay or MFU.
3 The SPi system is current-controlled. engine speed by moving the throttle lever
directly. It is possible' to by-pass the idle
4 The injector resistance is normally 1.1 to
1.5 ohms. switch by disconnecting one 'of the wires on
the pedal switch. MEMS will assume a fault,
and set a default value. The engine will then
16 Phase sensor (CID) respond to throttle lever movement. . 14.11 Check the throttle pot voltage
3 Once testing is complete, the pedal switch output with the aid of a voltmeter
wire must be reconnected, and a FCR used to
clear the ECMof any logged faults. become open-circuit and remain so - even as
4 Check that the terminal pins are pushed the throttle is opened fully.
1 Refer to the notes at the start of Section 11,
home and making good contact with the 15 If the pedal switch does not behave as
and refer to the relevant Section of Chapter 4.
pedal switch. described, and if it is not prevented from
2 The CID phase sensor is located adjacent
to the camshaft. opening or closing fully by a binding throttle
Checking pedal switch operation linkage, the ECM p.edalswitch is suspect.
3 Unfortunately, no data is available for CID 5 The two wires to the pedal switch multi-
resistance, but failure is likely to be indicated plug connector are earth and idle signal.
bya short- or open-circuit reading. 6 With the engine stopped, and ignition on, 21 Throttle potentiometer
connect the voltmeter negative probe to an sensor (TPS)
17 MAP sensor engine earth.
7 Connect the voltmeter positive probe to the
wire attached to the pedal switch signal 1 Refer to the notes at the start of SectiOn 11,
terminal number 2.,The meter should indicate and refer to the relevant Section of Chapter 4
zero volts. (see illustration 14.11).
1 Refer to the notes at the start of Section 11, 8 If zero volts cannot be obtained:
and refer to the relevant Section of Chapter 4
(see illustration 14.10). a) Check the pedal switch earth connection.
b) Make the pedal switch resistance tests
22 Stepper motor
2 The MAP sensor is incorporated. into the
(below).
ECM, and separate voltage tests are not
possible. 9 Crack open the throttle. The voltage should
3 Performance of the MAP sensor can be rise to 5.0 volts.
10 If the voltage is low or non-existent: 1 Switch the ignition key to the 'on' position.
quickly evaluated by a suitable FCR attached 2 After 5 seconds, switch the ignition key to
to the serial port. Select Datastream; the a) Check that the pedal switch idle terminal
is not shorted to earth. the 'off' position. The stepper motor plunger
values should be similar to those detailed in .
should fully retract, and then step to the
the MAP table (see Chapter 4, Section 18). b) Disconnect the pedal switch connections, correct position (according to temperature),
and check for 5.0 volts at the signal ready for the next engine start. After
terminal.If there is no voltage, check for 15 seconds, the main relay will audibly 'click
18 Airtemp,erature sensor (ATS) continuity of the signal wiringbetween the out' . If this operation is completed
pedal switch and the ECM. satisfactorily, it is probable that the stepper
11 If the pedal switch wiring is satisfactory, motor condition is also satisfactory.
check all voltage supplies and earth
1 Refer to the notes at the start of Section 11, connections to the ECM. If the voltage Stepper motor tests
and refer to the relevant Section of Chapter 4. supplies and earth connections are 3 Check for nbv to the stepper motor supply.
2 The ATS is mounted in the air inlet casing satisfactory, the ECM is suspect. 4 Connect a DC voltmeter to each of the
(MPi) or in the air filter casing (SPi).
Pedal switch resistance tests earth pins in turn (see illustrations 14.12
--~-"""'~ ~ .- and 14.13).
12 Connect an ohmmeter between the earth 5 Switch the ignition key on and off. A voltage
19 CGolant temperatUre sensor terminal 1 and terminal 2. should be briefly seen as the stepper motor
(CTS) 13 With the pedal switch closed, the actuates.
ohmmeter should indicate very close to zero 6 Disconnect the stepper motor multi-plug,
--'-"""""''''
ohms. and check the resistance from pin 5 to pins 1,
1 Refer to the notes at the start of Section 11, 14 Slowly open the throttle, and as the pedal 2, 3 and 4 in turn; 16 ohms should' be
and refer to the relevant Section of Chapter 4. switch cracks open, the resistance should obtained between pin 5 and e?ichearth pin.

Throttle Pedal Switch wire colours believed to be pink/grey and black/pink

I
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