Injection double relay (1304)
The double injection relay is controlled directly by the injection ECU
The double injection relay is connected to the injection harness by a 15 way connector (fastening of the connector by clamping bow)
It has 3 operating states
Ignition off: permanent +12volt supply to ECU (the supply to the memory and the auto-adaptation of the ECU are preserved)
Ignition on
- ECU supplied with "+" after ignition
- The fuel pump is supplied for 2 to 3 seconds after this time, the supply is cut off if the engine is not started
Engine running, components supplied
- Injection ECU
- Fuel pump
- Injectors
- Ignition coil
- Canister discharge electrovalve
- Oxygen sensor heating element (downstream oxygen sensor, upstream oxygen sensor)
Vehicle speed sensor (1620)
Role
The sensor informs the ECU on the vehicle speed
The role of the injection ECU in terms of the information received
- To work out the vehicle speed
- To work out the ratio of the gear engaged
- To improve idling speed when the vehicle is moving
- To optimise acceleration
- To reduce engine hesitation
Description
"Hall effect" sensor
- 5 impulses per metre
- 8 impulses per revolution
Electrical special features
Allocation of channels of connector
- Terminal 1: + 12 volts supply (double injection relay)
- Terminal 2: earth
- Terminal 3: signal
Location
The sensor in located in the gearbox
Engine speed sensor (1313)
Role
The sensor is located opposite the teeth of the flywheel
The role of the injection ECU in terms of the information received
- Checking the engine speed
- To determine the position of the crankshaft
- Calculation of the ignition advance
- To regulate the idle speed
Description
The sensor is of the inductor type
Components of the sensor
- A permanent magnet
- An electric winding
The sensor provides an electrical signal every time a tooth on the flywheel passes by (change in magnetic field)
The 58 teeth are used to work out the engine speed
The 2 missing teeth are used to work out the crankshaft position (no signal)
NoteThe air gap value is not adjustable
Electrical special features
Allocation of channels of connector
- Terminal 1: signal
- Terminal 2: earth
- Terminal 3: screening (*)
(*) according to version
Resistance between channels 1 and 2: 300 to 400 Ω
Features of the signals emitted: variable frequency alternating voltage
Location
Location: on the clutch housing
The camshaft position sensor (1115)
Role
The role of the injection ECU in terms of the information received
- To synchronise fuel injections with respect to the position of the pistons
- To recognise top dead centres
- To determine misfires
Description
"Hall effect" sensor
The camshaft sensor provides a square signal for the injection ECU
Electrical special features
Allocation of channels of connector
- Terminal 1: + 12 volts supply
- Terminal 2: signal
- Terminal 3: earth
The voltage slots are between 0 and 12 volts
Signal emitted
- Presence of metal earth opposite the sensor: 0 Volts
- Absence of metal earth opposite the sensor: 12 Volts
Location
Location: to cylinder head, opposite a target driven by the camshaft
Engine coolant temperature sensor (1220)
Role
The engine coolant temperature sensor informs the ECU about the engine coolant temperature
The role of the injection ECU in terms of the information received
- To adjust the starting flow
- Adjust the idling speed
- To obtain an accelerated idle speed which decreases as the engine heats up
Description
The sensor consists of a CNT-type resistor (negative temperature coefficient resistance)
The more the temperature increases, the more its resistance value is reduced
Electrical special features
Supply: injection ECU
Allocation of channels of connector
- Terminal 1: + 5 volts supply
- Terminal 2: signal
Electrical features
- Resistance at 20 °C = 2500 ohms
- Resistance at 80 °C = 300 ohms
Air temperature sensor (1310)
Role
The air temperature sensor informs the ECU of the temperature of the air admitted
The role of the injection ECU in terms of the information received
- Calculate the density of the ambient air
- Determine the quantity of fuel to be injected
Description
The sensor consists of a Negative Temperature Coefficient (NTC) resistor
The more the temperature increases, the more its resistance value is reduced
Electrical special features
Electrical features
- Resistance at 20 °C = 2500 ohms
- Resistance at 80 °C = 300 ohms
Knock sensor (1120)
Role
The engine knock information, transmitted by the sensor, enables the ECU to correct the ignition advance (reduction)
Knock is a vibratory phenomenon due to an exploding combustion of the air/fuel mixture in one of the 4 cylinders
The sensor transmits voltage peaks to the injection ECU when there is knocking
After engine knocking information, the ECU reduces the ignition timing, and simultaneously enriches the air-fuel mixture
Electrical special features
Supply: injection ECU
Allocation of channels of connector
- Terminal 1: + 5 volts supply
- Terminal 2: signal
- Terminal 3: screening (*)
(*) according to version
Location
Location: cylinder block
Upstream oxygen sensor (1350)
Role
Location: the oxygen sensor is located in the exhaust line, between the engine and the catalytic converter
These hydrocarbons alter the state of the reference air in the sensor and therefore the mixture signal accuracy
The role of the injection ECU in terms of the information received
- To determine the fuel / air mixture (richness)
- Mixture regulation
Description
The oxygen sensor informs almost continuously the ECU about the air-fuel mixture ratio
The "rich" or "lean" mixture information is given by 0 to 1 V voltages
- Lean mixture = 0,1V
- Rich mixture = 0,8V
A heating device placed inside the sensor enables it to rapidly reach its operating temperature (+ 300°C)
Electrical special features
The sensor is equipped with a 4 way caliper connector
Allocation of channels of connector
- Terminal 1: + 12 volts supply (oxygen sensor heater)
- Terminal 2: earth
- Terminal 3: + signal
- Terminal 4: - signal
Throttle potentiometer (1316)
Role
The throttle potentiometer informs the injection ECU on the position of the fuel throttle
The information supplied by this unit is used to
- Identify the position of "no throttle" or "full throttle"
- Determine the strategies of acceleration, deceleration and injection cut-off
- Inform the automatic gearbox ECU (*)
(*) according to version
Features of the automatic gearbox
The injection ECU sends the position of the fuel throttle to inform the gearbox ECU of the engine load
The throttle potentiometer is also used to perform the "kick-down" function (no tight spot)
Electrical special features
Supply: injection ECU
Allocation of channels of connector
- Terminal 1: earth
- Terminal 2: + 5 volts supply
- Terminal 3: signal
The voltage signal delivered to the ECU by this unit varies from 0 to 5 V according to the position of the throttle
Power steering pressure switch (7001)
Role
The steering pressure switch allows the engine ECU to increase the engine idling speed when parking
Conditions for increasing the idling speed
- Vehicle speed lower than 4 kph
- Pressure switch activated (power-assisted steering)
Location
On the union between the power assisted steering valve and pump
Injection ECU (1320)
Role
The ECU controls the ignition and the injection depending on the various parameters received
These parameters are
- The engine speed and the crankshaft position (TDC sensor - camshaft position sensor)
- The inlet air pressure (pressure sensor)
- The throttle position (throttle potentiometer)
- The engine temperature (coolant thermistor)
- The temperature of the air drawn into the cylinders (air temperature sensor)
- The speed of the vehicle (vehicle speed sensor)
- The oxygen content of exhaust gases (oxygen sensor)
- The pinking (knock sensor)
- The air conditioning demand
- The battery voltage
- The pressure in the power assisted steering circuit
- Automatic gearbox ECU
By making use of the information, the ECU controls
- The ignition advance and the coil charging time
- Adjustment of idling speed: Engine temperature, battery voltage, parking, automatic gearbox and air conditioning
- The amount of fuel injected, proportional to the injector opening time
- The idling speed regulation
- The fuel pump
- The fuel vapour recycling (canister bleed electrovalve)
- The injection cut-off on overspeed and deceleration
- The air conditioning cut-off
- The trip computer (instant consumption)
- The tachometer
- Diagnostic warning lamp
- The oxygen sensor heating element (downstream oxygen sensor, upstream oxygen sensor)
- The secondary air pump (air injection into the exhaust function)
- The automatic gearbox ECU: throttle potentiometer, engine speed, coolant temperature, engine torque
The ECU also controls the following functions
- Emergency strategies
- The diagnostic with memorisation of failures using a diagnostic tool
Allocation of channels of connector
ECU connector: 88-way
WarningInjection system BOSCH MP7.2: channels 56 to 88 are not used
| channel No. | matching the tracks | injection system: MP7.2 | injection system: MP7.3 (engine TU) | injection system: MP7.3 (engine XU) |
|---|---|---|---|---|
| 1 | earth: ignition power stages | x | x | x |
| 2 | (not used) | - | - | - |
| 3 | output: stepper motor control | x | x | x |
| 4 | output: stepper motor control | x | x | x |
| 5 | (not used) | - | - | - |
| 6 | power earth | x | x | x |
| 7 | input: torque reduction request information (BVA) | x | - | x |
| 8 | (not used) | - | - | - |
| 9 | input: power steering pressure switch | x | x | - |
| 10 | input: (+) signal for knock sensor | x | x | x |
| 11 | (not used) | - | - | - |
| 12 | input: coolant temperature information | x | x | x |
| 13 | input: oxygen sensor richness information (+) (before the catalytic converter) | x | x | x |
| 14 | input: inlet manifold air pressure | x | x | x |
| 15 | output: fuel pump relay control (earth) | x | x | x |
| 16 | output: throttle position signal (automatic gearbox ECU) | x | - | x |
| 17 | input: vehicle speed (vehicle speed sensor) | x | x | x |
| 18 | input: (-) signal for speed and position sensor | x | x | x |
| 19 | line L diagnosis | x | x | x |
| 20 | line K diagnosis | x | x | x |
| 21 | ignition on information | x | x | x |
| 22 | engine immobiliser dialogue line (transponder) | x | x | x |
| 23 | earth: petrol injectors | x | x | x |
| 24 | output: refrigeration compressor operation relay control | x | x | x |
| 25 | output: throttle position information (automatic gearbox ECU) | x | - | x |
| 26 | output: injector No 4 control (earth) | x | x | x |
| 27 | output: injector No 1 control (earth) | x | x | x |
| 28 | sensors earth | x | x | x |
| 29 | output: double coil control (cylinders 2 - 3) | x | x | x |
| 30 | output: double coil control (cylinders 1 - 4) | x | x | x |
| 31 | output: stepper motor control | x | x | x |
| 32 | output: stepper motor control | x | x | x |
| 33 | ECU supply in (+) by relay | x | x | x |
| 34 - 35 | (not used) | - | - | - |
| 36 | input: air conditioning demand information (by a temperature of AC-TH) | x | x | x |
| 37 | sensors earth | x | x | x |
| 38 | input: (-) signal for knock sensor | x | x | x |
| 39 | input: engine coolant temperature information (coolant temperature sensor) | - | - | - |
| 40 | input: oxygen sensor signal (-) (before the catalytic converter) | x | x | x |
| 41 | input: throttle position information (+) (throttle potentiometer) | x | x | x |
| 42 | + 5 volts supply (sensors) | x | x | x |
| 43 | output: diagnostic warning lamp (earth) | x | x | x |
| 44 | output: engine speed to instrument panel | x | x | x |
| 45 | input: camshaft sensor signal | - | x | x |
| 46 | input: engine speed sensor signal | x | x | x |
| 47 | output: current fuel consumption (trip computer) | x | x | x |
| 48 | input: wake up for injection ECU, wake up for ADC | x | x | x |
| 49 | battery permanent +: auto-diagnostic memories | x | x | x |
| 50 | output: control of the principal relay earth | x | x | x |
| 51 | output: canister bleed valve control | - | - | - |
| 52 | (not used) | - | - | - |
| 53 | output: injector No 2 control (earth) | x | x | x |
| 54 | output: injector No 3 control (earth) | x | x | x |
| 55 | earth: for the oxygen sensor heating (before the catalytic converter) | x | x | x |
| 56 - 66 | (not used) | - | - | - |
| 67 | input: EOBD warning lamp illumination request information | - | x | x |
| 68 | sensors earth | - | - | x |
| 69 | (not used) | - | - | - |
| 70 | input: oxygen sensor signal (-) (after the catalytic converter) | - | x | x |
| 71 | input: oxygen sensor signal (+) (after the catalytic converter) | - | x | x |
| 72 | input: body acceleration sensor signal (+) | - | x | x |
| 73 | (not used) | - | - | - |
| 74 | + 5 volts supply: throttle potentiometer | - | x | x |
| 75 | earth: camshaft position sensor (engine XU7) | - | - | x |
| 76 - 83 | (not used) | - | - | - |
| 84 | output: control of the air to exhaust injection pump relay earth | - | x | x |
| 85 | (not used) | - | - | - |
| 86 | earth: for the oxygen sensor heating (after the catalytic converter) | - | - | - |
| 87 - 88 | (not used) | - | - | - |