I'm just going to chip in here with some additional info as if and when you are testing there are specific events that take place after a certain time lapse that you may / may not be aware of and that may throw you off-track when you are testing. Pay specific attention to the door opening and timings and the consequences:
Other stuff is for reference.
Further on down, is some detailed info on testing that you might find useful.
Transponder Operated Anti-Theft Device
| Key
Reference | Designation |
1 | Permanent +. + after ignition and earth |
2 | Alarm LED |
8 | Key-in-ignition audible warning |
14 | Centralised diagnostic socket (16 or 30 channels) |
15 | Engine management computer (ECM) |
16 | Door open warning lamp |
17 | Transponder warning lamp |
18 | Transponder analogue module |
19 | Integrated transponder |
21 | High frequency remote control unit |
25 | Doors open switch assembly |
8630 | Body computer (CPH) |
|
Operation
| (14) Centralised diagnostic socket .
(18) Transponder analogue module.
(19) Integrated transponder.
(26) Driver’s door switch.
(27) injection ECU (petrol or diesel).
(29) diesel injection pump.
(28) Injection double relay (supply to the ECM).
(8630) Body computer (CPH). |
Detecting a key left in the ignition
When the ignition switched supply is cut off and the driver’s door is opened, the body computer performs a search to detect if the key has been left in the ignition.
If the body computer detects a key with a recognised transponder code:
- The key in ignition audible warning is activated and generates a signal
- The signal is initially fixed for 0,6 seconds, then pulsed at a frequency of 2 Hz
The audible signal stops if the key is removed from the ignition or if the driver’s door is shut.
The audible signal will continue to sound for 30 seconds after the ignition is switched off if no action is taken.
Unlocking the fuel injection ECU
When the ignition key is in the "ignition on" position:
- The red LED goes out (unless the alarm is armed), and the unlocking warning lamp on the instrument cluster comes on
- The system reads the key code
- The ECM informs the body computer of its current state (locked or unlocked)
If the ECM is in the "unlocked" state:
- The warning lamp on the instrument cluster goes out
- The vehicle can be started
If the ECM is in the "locked" state, or if no information is received about the state of the ECM:
- The body computer recognises the key code
- The body computer transmits a command to the ECM to unlock
- The ECM replies by relating its new state
Note: If the new state is "unlocked", the command to unlock having been accepted by the ECM, the warning lamp on the instrument cluster will go out.
If the key code is not recognised by the body computer (command to unlock not accepted by the ECM, or if no information is received about its state): The warning lamp on the instrument cluster flashes at a frequency of 2.5 Hz and the audible warning emits a continuous signal either until the ignition is switched off or for 30 seconds.
Locking the fuel injection ECU
The body computer automatically initiates the locking procedure:
- Either 5 minutes after the ignition is switched off
- Or 10 seconds after the driver’s door is opened (if the ignition switched + has been cut and if the door is opened within 5 minutes after the ignition is switched off)
Note: If the driver’s door is already open when the ignition is switched off, the locking procedure will be initiated 10 seconds after the ignition is switched off.
Locking procedure:
- The body computer resupplies the ECM via the injection double relay ( 1), or the anti-theft relay (2)
- The ECM informs the body computer of its current state
Note: (1) Electronically operated diesel and petrol engines. (2) Diesel engines with a mechanical pump.
If the ECM is "locked":
- The body computer cuts the supply to the ECM (resupply relay)
- The alarm LED flashes at a frequency of 2 Hz
If the ECM is "unlocked":
- The body computer transmits a command to the ECM to lock
- The ECM informs the body computer of its current state: The alarm LED flashes at a frequency of 1 Hz
If the new state is locked:
- The body computer cuts the supply to the ECM
- The frequency with which the LED flashes changes from 1 Hz to 2 Hz
If the new state is unlocked, or if no information is received about the state:
- The lock command is repeated every minute
- If the ECM is still not locked after 4 new attempts, then the body computer will cut off its supply (supply restored when the ignition is next switched on)
- The frequency with which the LED flashes changes from 1 Hz to 2 Hz
Note: If the ignition "+" is switched on again before the ECM supply is cut off, the locking procedure is interrupted and cancelled.
Anti Theft Function Checks
Part (1) Checking the Engine ECU Lock
A) By Using a Key Shield
A metallic shield inserted between the analogue module antenna and the electronic device located in the key prevents the former from reading the latter . A faulty key can be simulated in this way. This shield can be made by drilling a 8 mm hole in the centre of a suspension sphere thread protection cap (1).
Procedure:
- Switch off the ignition, Open the driver’s door and wait for 10 seconds (the key-in-ignition audible warning stops).
- Insert the ignition key into the 8mm hole drilled in the shield.
- Switch on the ignition using the screened ignition key, The transponder warning lamp in the instrument panel flashes, and the audible warning emits a pulsed sound.
- If the ECU is correctly locked, the engine cannot be started.
B) By removing the ignition on information
Procedure:
- Switch off the ignition , Open the driver’s door and wait for 10 seconds (the key-in-ignition audible warning stops)
- Remove fuse F2
- Switch on the ignition, The transponder warning lamp in the instrument panel does not come on
- Attempt to start the engine, The transponder warning lamp in the instrument panel flashes and the audible warning emits a pulsed sound
- If the ECU is correctly locked, the engine cannot be started
C) Using the transponder warning lamp in the instrument panel
Procedure:
- Switch off the ignition, Open the driver’s door and wait for 10 seconds (the key-in-ignition audible warning stops).
- Close the driver’s door.
- Switch on the ignition, Observe the time required to unlock the engine ECU (the time that the transponder warning lamp in the instrument panel is on for).
- Switch off the ignition.
- Switch on the ignition, Observe the time that the transponder warning lamp in the instrument panel is on for, Engine control unit unlocked.
The second time the ignition is switched on, as the CPH does not have to unlock the ECU, the warning lamp should come on for a shorter period of time.
Note: The time that the warning lamp is on for also depends on the type of engine ECU fitted to the vehicle, Certain ECUs respond faster than others.
Using the LED for vehicles fitted with an alarm
For vehicles fitted with an alarm, and depending on the CPH configuration (programming), the alarm LED can also be used to check the state of the engine ECU.
- Ignition off, the LED stays off then starts to flash 10 seconds after the driver’s door is opened. The LED will flash slowly (1 Hz) to indicate that the CPH has been informed that the engine ECU is locked.
- Ignition off, the LED will continue to flash until the CPH is informed that the engine ECU has been unlocked.
Caution: When ignition is switched on, the LED flashes immediately if the CPH has not been informed that the engine ECU is unlocked.
Part (2) Symptoms related to the immobiliser function
Part (3) The diagnostic equipment cannot communicate with the CPH
When carrying out a diagnostic check of the CPH with diagnostic equipment, the vehicle lock motors are not activated; The diagnostic equipment reveals a communication failure with the ECU
Possible fault causes | Method of checking |
Faulty connection with the diagnostic socket | - Connect the electrical test unit to the CPH
- Check the continuity and isolation of the connection between terminal 6 of the diagnostic socket and terminal 11 of the 26-way yellow connector of the CPH
- Also check that the diagnostic equipment is working correctly
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Faulty body computer | - Connect the electrical test unit to the CPH
- Check the plus permanent electrical supply between terminals 4 and 13 and terminals 1 and 13 of the 15-way black connector of the CPH
- If not, Check fuses F15 and F25
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Part (4) The engine ECU is not locked (vehicle not protected)
The door-open warning lamp does not come on if only the driver’s door is open
Possible fault causes | Method of checking |
There is dialogue between the diagnostic equipment and CPH | - The CPH will not operate during dialogue with the diagnostic instrument
- Check that the CPH diagnostic check has been fully terminated if locking has not taken place
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No driver’s door open information | - Check the connection to the driver’s door lock
- If there is no driver’s door information, the engine ECU will only be locked 5 minutes after the ignition is switched off
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Opening the driver’s door will cause the door-open warning lamp to come on
Possible fault causes | Method of checking |
The engine ECU has not been initialised | Select the engine ECU initialisation during the CPH diagnostic check
The vehicle access code, recorded on the customer’s confidential card, must be available
After terminating the diagnostic operation, check that the warning lamp works correctly and ensure that the CPH locks the engine ECU properly (see Part (1)). |
The CPH has not been initialised | - The transponder warning lamp in the instrument panel does not come on when the ignition is switched on.
- Using the diagnostic equipment to read the parameters, Check that the CPH has been properly initialised (number of keys initialised is not zero).
- Otherwise initialise the CPH.
- It is necessary to have available both the vehicle access code, recorded on the customer’s confidential card, as well as all the vehicle keys.
- After terminating the diagnostic operation, check that the warning lamp works correctly and ensure that the CPH locks the engine ECU properly (see Part (1)).
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No electrical resupply to the engine ECU after switching off the ignition | - Connect the electrical test unit to the CPH
- Ignition off, driver’s door closed.
- There should be 0 volts at terminal 7 of the 26-way yellow connector of the CPH.
- Driver’s door open.
- The CPH should resupply the ECU 10 seconds after the ignition is switched off.
- For approximately one second there should be U ð 12 volts.
- Check the continuity and isolation in relation to the earth of both the resupply line and resupply relay (if fitted).
- If the CPH is faulty and the vehicle is fitted with a resupply relay, replace both of them.
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There is no dialogue between the CPH and the engine ECU | - Check the continuity and isolation in relation to the earth between terminal 6 of the 26-way yellow connector of the CPH and the engine ECU.
- Using a voltmeter, check that a change occurs at terminal 6 during the locking phase.
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(*): If the initialisation procedure has been interrupted, the number of keys memorised may not be zero even though the CPH is not initialised.
Part (5) The engine will not start
When ignition is switched on, the transponder warning lamp in the instrument panel flashes, and the audible warning emits a pulsed sound
Possible fault causes | Method of checking |
Key faulty or not recognised | - Switch on the ignition using the other keys.
- If none of the keys will start the engine, there could be a problem with the antenna or the CPH.
- Check that the antenna connector is properly connected.
- If this is the case, Connect the electrical test unit to the CPH.
- Check the transponder analogue module.
- If another key starts the engine, the key is faulty or hasn’t been initialised.
- Initialise the keys.
- It is necessary to have available both the vehicle access code, recorded on the customer’s confidential card, as well as all the vehicle keys.
- The initialisation procedure is interrupted once a faulty key is detected.
- Initialise the keys again without the faulty key.
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No supply to the engine ECU | - Connect the electrical test unit to the injection ECU and check that it is receiving a supply.
- Check the fuses and the double relay.
- In the case of diesel pump modules, use the ADC test cable to check the supply.
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When ignition is switched on, the transponder warning lamp in the instrument panel does not come on. When trying to start the engine, the transponder warning lamp in the instrument panel flashes and the audible warning emits a pulsed sound
Possible fault causes | Method of checking |
No ignition switched "+" information | - Using the diagnostic equipment to read the parameters, check that the CPH is correctly receiving the ignition switched "+" information.
- If not, Check the fuse F2.
- If the fuse is in good condition, connect the electrical test unit to the CPH.
- The ignition switched "+" must be present at terminal 5 of the 15-way black connector.
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When ignition is switched on, the transponder warning lamp in the instrument panel does not come on. The vehicle cannot be locked using the plip.
Possible fault causes | Method of checking |
There is dialogue between the diagnostic equipment and CPH | - The CPH will not operate during dialogue with the diagnostic instrument.
- Check that the CPH diagnosis has correctly terminated if the engine will not start.
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The CPH has not been initialised | - The transponder warning lamp in the instrument panel does not come on when the ignition is switched on.
- Using the diagnostic equipment to read the parameters, check that the CPH has been properly initialised (number of keys initialised is not zero).
- Otherwise initialise the CPH.
- It is necessary to have available both the vehicle access code, recorded on the customer’s confidential card, as well as all the vehicle keys.
- After terminating the diagnostic operation, check that the warning lamp works correctly and ensure that the CPH locks the engine ECU properly (see Part (1).
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Faulty body computer | - Connect the electrical test unit to the CPH.
- Check the plus permanent electrical supply between terminals 4 and 13 and terminals 1 and 13 of the 15-way black connector of the CPH.
- If not, check fuses F15 and F25.
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(*): If the initialisation procedure has been interrupted, the number of keys memorised may not be zero even though the CPH is not initialised.
Part (6) The engine does not stop When ignition is switched on
Possible fault causes | Method of checking |
The re-supply relay is faulty (if fitted). | - Check that the relay switch is not stuck.
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The CPH permanently controls the resupply of the engine relay | - Connect the electrical test unit to the CPH.
- Ignition off, driver’s door closed.
- There should be 0 volts at terminal 7 of the 26-way yellow connector of the CPH.
- Check the isolation in relation to the resupply line + 12 volts.
- If the CPH is faulty and the vehicle is fitted with a resupply relay, replace both of them.
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Part (7) The transponder warning lamp in the instrument panel does not come on when the ignition is switched on
Possible fault causes | Method of checking |
The warning lamp is faulty | - Ignition on, with the diagnostic equipment testing the actuators, check that the warning lamp comes on (for 0.5 second).
- If not, Check the fuse F12.
- If the fuse is in good condition, connect the electrical test unit to the CPH.
- Check the continuity and isolation of the warning lamp control line.
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The vehicle cannot be locked using the plip
Possible fault causes | Method of checking |
There is dialogue between the diagnostic equipment and CPH | - The CPH will not operate during dialogue with the diagnostic instrument.
- Check that the CPH diagnosis has correctly terminated if the engine will not start.
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The CPH has not been initialised | - The transponder warning lamp in the instrument panel does not come on when the ignition is switched on.
- Using the diagnostic equipment to read the parameters , Check that the CPH has been properly initialised (number of keys initialised is not zero).
- Otherwise initialise the CPH.
- It is necessary to have available both the vehicle access code, recorded on the customer’s confidential card, as well as all the vehicle keys.
- After terminating the diagnostic operation, check that the warning lamp works correctly and ensure that the CPH locks the engine ECU properly (see Part 1).
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Faulty body computer | - Connect the electrical test unit to the CPH.
- Check the plus permanent electrical supply between terminals 4 and 13 and terminals 1 and 13 of the 15-way black connector of the CPH.
- If not, check fuses F15 and F25.
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(*): If the initialisation procedure has been interrupted, the number of keys memorised may not be zero even though the CPH is not initialised.
When ignition is switched on, the transponder warning lamp in the instrument panel does not come on. When trying to start the engine, the transponder warning lamp in the instrument panel flashes and the audible warning emits a pulsed sound
Possible fault causes | Method of checking |
No ignition switched "+" information | - Using the diagnostic equipment to read the parameters, check that the CPH is correctly receiving the ignition switched "+" information.
- If not, check the fuse F2.
- If the fuse is in good condition, connect the electrical test unit to the CPH.
- The ignition switched "+" must be present at terminal 5 of the 15-way black connector.
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Part (8) The key-in-ignition audible warning does not work
When ignition is switched on, the transponder warning lamp in the instrument panel does not come on. The vehicle cannot be locked using the plip. See Part (7).
The door-open warning lamp does not come on if only the driver’s door is open
Possible fault causes | Method of checking |
No driver’s door open information | - Check the connection to the driver’s door lock.
- If there is no driver’s door information, the engine ECU will only be locked 5 minutes after the ignition is switched off.
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The door-open warning lamp comes on when only the driver’s door is open
Possible fault causes | Method of checking |
Faulty audible warning | - With the diagnostic equipment testing the actuators, check the operation of the audible warning (for 0.5 second).
- Check that the audible warning is receiving the correct supply.
- Check the continuity and isolation of the audible warning control line.
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Faulty body computer | - Connect the electrical test unit to the CPH.
- Check that it controls the audible warning when the ignition is switched off with a door open.
- It must read:
- Ignition on: U ≈ 12 V.
- When ignition is switched on: U ≈ 0 V.
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