Procedure
2. Opening this connector, inside the lid is a schematic of the connections.
It is possible to scope O2 sensors and various other systems from here but we
will be limited to code reading.
3. Ensure the ignition is off, the handbrake is applied and the gearbox is in
Neutral or Park.
4. Take a piece of Insulated wire, approximately 2.5mm^2, and strip off
1/4"/0.5cm of insulation from each end. Form the wire into a loop about the
middle to create a jumper-wire. Solid wire is preferred.
5. Connect this jumper-wire across the connections labled "GND" & "TEN". Ensure no
other connectors are connected, and no strands are wandering about if stranded
wire is used.
6. Turn the ignition to ON but do not start the car, watch the CEL as it flashes
out any codes. If it does not flash confirm the connections, if it still does
not flash then no codes have been stored by the ECU.
7. Codes are flashed out according to the lowest code first, and repeated after a
pause of 4 seconds. The format is akin to morse code, in that a short flashes
represent 1s and longer flashes 10s. Thus flashes of --- --- - - - - would
represent a code of 24 for the (rear) oxygen sensor. Oxygen sensor failures
are the most common cause of CELs.
8. To clear codes, disconnect the negative battery terminal for 2 minutes with
a door left open or apply the brakes.
9. Turn the Ignition to OFF before removing the jumper wire, and ensure when
removing the jumper wire no other connections are touched.
10. If more than one code is present, it can be worth clearing all codes and then
checking them again to see which re-occur. It is not uncommon for sporadic codes
to appear under certain fault conditions - so requiring them to come back as
confirmation is strongly advised.
Method
2. Opening this connector, inside the lid is a schematic of the connections.
It is possible to scope O2 sensors and various other systems from here but we
will be limited to code reading.
3. Ensure the ignition is off, the handbrake is applied and the gearbox is in
Neutral or Park.
4. Take a piece of Insulated wire, approximately 2.5mm^2, and strip off
1/4"/0.5cm of insulation from each end. Form the wire into a loop about the
middle to create a jumper-wire. Solid wire is preferred.
5. Connect this jumper-wire across the connections labled "GND" & "TEN". Ensure no
other connectors are connected, and no strands are wandering about if stranded
wire is used.
6. Connect the Anode/+ve of the LED+Resistor or 12V-LED to the B+ terminal, and
the free resistor end (Cathode/-ve) to the FEN terminal. Ensure that nothing
else is connected or accidentally connected as B+ is a 30A 12V supply.
7. Turn the ignition to ON but do not start the car, watch the LED as it flashes
out any codes. If it does not flash confirm the connections, if still not
flash then you have no codes stored.
8. Codes are flashed out according to the lowest code first, and repeated after a
pause of 4 seconds. The format is akin to morse code, in that a short flashes
represent 1s and longer flashes 10s. Thus flashes of --- --- - - - - would
represent a code of 24 for the (rear) oxygen sensor. Oxygen sensor failures
are the most common cause of CELs.
9. To clear codes, disconnect the negative battery terminal for 2 minutes with
a door left open or apply the brakes.
10. Turn the Ignition to OFF before removing the jumper wire, and ensure when
removing the jumper wire no other connections are touched.
11. If more than one code is present, it can be worth clearing all codes and then
checking them again to see which re-occur. It is not uncommon for sporadic codes
to appear under certain fault conditions - so requiring them to come back as
confirmation is strongly advised.
24 - Rear Oxygen Sensor.
Last Upload: 16th February, 2002. V1.50a
ECU Code Reading
ECU Code Readings
93-96 model cars - DIY reading is possible, OBD-I used.
93-96 UK cars - lack a Check Engine Light, CEL, but DIY code reading possible, OBD-I used.
96+ model cars - OBD-II capable reader is required.
For non-UK 93-96 cars with CEL:
Items required:
6" of cable, insulated, preferably solid core of 2.5mm^2.
1. Open the hood/bonnet and locate the black oblong diagnostic connector
behind the battery with "DIAGNOSTIC" printed in raised type on the top.
Locate the terminals "TEN" & "GND", notice there is a "B+" terminal nearby which
is a 30A +12V feed from the battery and no loose strands of wire must touch it.
For cars without CEL (eg, UK cars):
Items required:
6" of cable, insulated, preferably solid core of 2.5mm^2.
A standard LED (Light Emitting Diode) & 1k-ohm resistor (soldered
to the cathode/-ve of the LED) or a standard "12V LED".
1. Open the hood/bonnet and locate the black oblong diagnostic connector
behind the battery with "DIAGNOSTIC" printed in raised type on the top.
Locate the terminals "TEN" & "GND", notice there is a "B+" terminal nearby which
is a 30A +12V feed from the battery and no loose strands of wire must touch it.
Common Codes:
12 - Throttle Position Sensor.
Throttle Position Sensor failure usually accompanies poor or sluggish
performance that is markedly poor. The sensor itself is a carbon track
which can wear or fail resulting in voltage spikes. Such voltage spikes
cause the ECU to go into "limp mode" substituting values for the TPS by
interpolating other sensor data.
Very common from 60k miles onwards, causing a reduction in fuel mileage
due to slightly rich running. Replacements are 45ukp/55-60$US for Universal
equivalents which splice into the old sensors connector, rising to 100-120$US
for one with factory connector on it (if the old is not re-used).
URL: http://homepage.ntlworld.com/dorothy.bradbury/probemx/p_m18.htm