Stabilizer System, ESP: Diagnosis Saab 9-5 I рестайлинг 2

Diagnostics

The control module monitors its own internal functions as well as the components included in the system. A DTC will be generated in the event of an internal control module fault. The ESP, TCS and ABS functions will be disengaged and the warning lamps for the ABS, foot brake, central warning lamp and ESP OFF switched on.

Diagnostic help

The control module monitors the circuit by feeding a low current on pin 30 which is grounded by the brake pedal lamps.

DTC generated in ESP control module.

Scheme 10

Several other systems in the vehicle need to know the wheel speed. The ESP control module is connected to the P-bus and transmits information about the speed of each wheel.

This information is processed in the main instrument unit into vehicle speed in km/h (mph). The speed is corrected to the tyre size that has been programmed. This vehicle speed is then sent out over the I-bus.

The engine management system is connected to the P-bus and therefore has access to the same speed information.

Note. In cars with a 2.2 l diesel engine, vehicle speed data is sent directly from the ESP control module (pin 40) to PSG 16 (pin 34).

Scheme 11

Scheme 12

Speed information can be sent even when the ABS, foot brake, ESP OFF or central warning lamps are on. The information is sent as long as one of the rear wheel sensors is working and the control module is working and supplied with power.

For more information on wheel speed on the bus, see Electrical systems, SYSTEM OVERVIEW, BUS AND DIAGNOSTIC COMMUNICATION, PETROL (2006) or SYSTEM OVERVIEW, BUS AND DIAGNOSTICS COMMUNICATION, PETROL (2007) and main instrument unit, SYSTEM OVERVIEW (2006) or SYSTEM OVERVIEW (2007) .

Scheme 13

Diagnostics Communication

Diagnostics communication is performed via the cable from pin 11 of the ESP control module to pin 8 of the data link connector, and from there directly to the diagnostic instrument.

The diagnostic tool communicates digitally and serially with the ESP system. With digital communication, the difference in voltage between the lead and ground has two values, in this case about 0 V and B+. The information is coded so that different combinations of 0 V and B+ pulses have different meanings.

With serial communication, the information is sent in "packets" which are sent one after the other in very quick succession.

Scheme 14

Scheme 15

If communication with the system cannot be established, the fault could either be in the car or the diagnostic tool. If the diagnostic tool cannot establish communication with the same system in another car, then the fault is in the car.

First check that the control module is active - it should test the ABS warning lamps as soon as the ignition is switched on. If the control module is active, then the fault can probably be traced to the lead between it and the data link connector.

The control module performs a valve test each time the ignition is switched on. This test takes place at the same time as the pump-motor test and the valves are actuated for 20 ms.

Scheme 16

1. Front left pressure increase valve
2. Front right pressure increase valve
3. Pressure relief valve, front left
4. Front right pressure relief valve
5. Return pump
6. Brake caliper, front left
7. Brake caliper, front right
8. Brake caliper, rear left
9. Brake caliper, rear right
10. Front left inlet valve
11. Front right inlet valve
12. Rear left inlet valve
13. Rear right inlet valve
14. Front left outlet valve
15. Front right outlet valve
16. Rear left outlet valve
17. Rear right outlet valve
18. Accumulator chamber
19. Brake pressure sensor
20. Check valve
21. Check valve

In the event of erroneous engine torque information, the diagnostic trouble code C1928 is set, the ESP/TCS function is disabled and the ESP OFF lamp lights up.

In the event of a fault in the Trionic system's throttle control (limp-home), the CHECK ENGINE lamp will come on and the fault can be found in the ECM.

If the ESP control module is programmed for the wrong engine variant or transmission, diagnostic trouble code C0551 is generated.

Scheme 17

Pedal position data is sent by the engine management system over the P-bus. See also PEDAL SENSOR

The ESP control module uses the information on pedal position to determine the degree of wheel spin to allow during ESP/TCS modulation. The system considers the pedal position to be the degree of aggressiveness the driver requests and allows a greater degree of wheel spin the more the pedal is depressed (pedal position increases as a percentage).

Scheme 18

The ESP control module receives information about current engine speed from the engine management system via the P-bus. The control module uses this information when calculating the current drive wheel torque.

When engine torque and the current ratio are known, the control module can calculate the drive wheel torque. Drive wheel torque is used to calculate the magnitude of brake/engine torque limitation during ESP/TCS modulation.

Scheme 19

Scheme 20

The ESP function lamp is located on the left-hand side of the main instrument unit (in the tachometer). The lamp comes on when the ESP or TCS operate.

Fault diagnosis strategy for electronic systems

1. The customer's description of the problem constitutes a basis for the fault diagnosis strategy. If necessary, the customer must demonstrate the trouble on the car to avoid misunderstandings.
2. In certain cases, the function may be correct. 2.a. Good product knowledge is required to decide this. 2.b. If the function is correct, this must be explained to the customer.
3. If the function is judged to be faulty, the car should be repaired. Saab's fault diagnosis strategy assumes that the technician is familiar with the customer's description of the problem. So note the customer's complaint and any other observations on the job sheet.
4. The technician obtains a readout of the diagnostic trouble codes from all systems. A malfunction in one system can often be caused by a fault in another system.
5. The car may contain diagnostic trouble codes which are secondary faults or which have been incorrectly generated. 5.a. Compare the customer complaint with the symptom description for the various diagnostic trouble codes. WIS has a quick search function for this purpose. 5.b. If the symptom description for a diagnostic trouble code matches the customer's complaint, this diagnostic trouble code is probably caused by the primary fault. Repair as per instructions.
6. If there is no match with diagnostic trouble codes or symptoms, the technician must diagnose the fault himself. 6.a. Search in WIS under fault diagnosis for symptoms in the system where the fault exists. Also check whether there is a TSB/MI in force. 6.b. If the symptom description in the current system matches the complaint, the right fault diagnosis description has probably been found. Repair as per instructions.
7. Certain fault symptoms can be remedied by reprogramming the control module. 7.a. Does the customer complaint stem from a known software problem in a programmable control module? 7.b. Reprogram the control module following the instructions in SPS.
8. If there is no match with diagnostic trouble codes or symptoms, the technician must diagnose the fault himself. Good technical product knowledge is required to solve this type of problem.
9. A final check must be carried out after the repair.
10. The car is ready.

Explanation of valve test

1. From the Activate menu, select valve test for the wheel in question. IMPORTANT: The test can only be performed when the car is stationary.
2. Rotate the wheel by hand. The wheel should rotate freely. If you respond YES, the inlet valve is closed. The passage from the master cylinder to the wheel cylinder is closed.
3. The inlet valve is closed. The valve has gone into PRESSURE HOLDING MODE. The passage is closed and there is no brake pressure to the wheels.
4. The wheel should rotate freely. If you respond YES, the inlet valve and passage are opened. Brake pressure can go to the wheel.
5. The wheel should be locked. If you respond with YES, the outlet valve opens and the return pump starts. Brake fluid returns from the wheel cylinder with the aid of the return pump.
6. The wheel should rotate freely.
7. The last message on the display shows that the test has been completed.
8. If a fault arises while the test is in progress or you answer NO to any of the questions "Valve test failure, see WIS Brakes (ESP 8.0)" will appear on the display.

Scheme 21

It is our experience that the majority of control modules returned to us for repair or replacement under warranty are in perfect working order. In these cases, fitting a new control module has obviously not cured the fault. Therefore, go through all the following points carefully before changing the control module

Scheme 22

1. Check the latest edition of TIS2000 to see whether the problem can be solved with a control module software update (for control modules that can be reprogrammed). IMPORTANT: Avoid SPS programming unless it is absolutely necessary. It is extremely important to follow the instructions for SPS programming to avoid damaging the control module.
2. Check all grounding points and the power supply to the control module.
3. Check with a diagnostic tool that all the readings are plausible (several readings can affect one function).
4. Check with the diagnostics tool that all activations function normally. (Malfunction in one output circuit can affect another output circuit).
5. If the fault persists, the control module must be changed. Fill in the "Checklist for changing turbocharger and engine control module" before changing the control module and attach it when the control module is returned.
6. Control modules are sensitive to electrostatic discharges. Great care must be taken to follow the following procedure to avoid damaging internal components in the control module: Keep the control module in its packaging for as long as possible. Never touch the pins of a control module with your hands or clothing. Ground yourself by touching part of the car's body/engine. Unplug the connector from the car's control module. Place the exchanged control module in its return packaging without touching the pins. Ground yourself by touching part of the car's body/engine. Plug in the connector to the car's control module.

Scheme 23

A suitable instrument to use is a multimeter.

The ohmmeter must not be used to test components containing semi-conductors, e.g. control modules and relay with timing functions, etc.

When measuring resistance, the power supply to the system being tested must be disconnected as the measuring instrument generates a weak current in the circuit in question.

This is done to ensure that there is no current already in the tested circuit and that the correct reading is obtained.

Scheme 24

Scheme 25

1. Turn on the load.
2. Set the multimeter for measuring voltage and connect the negative lead of the voltmeter to a good grounding point.
3. Connect the positive lead of the voltmeter to the point where the voltage is to be read.
4. On the output side of switches/control modules, it is better to start checking from these and gradually work your way towards the load. When there is no longer a voltage reading, you will have gone past the break point.
5. On the input side of switches/control modules/consumers, it is better to start at the power source (normally a fuse) and then move gradually towards the switch/control module/consumer. When there is no longer a voltage reading, you will have gone past the break point.

Scheme 26

Scheme 27

1. Make sure the component or lead to be tested is not under tension (e.g. by removing the relevant fuse).
2. Set the multimeter for measuring ohms and connect the ohmmeter to each end of the component/lead to be tested.
3. Jiggle the relevant wiring harness while observing the ohmmeter. Normally, the resistance of a wiring harness is less than 1 ohm. Specified values apply to components.

Scheme 28

Scheme 29

1. Make sure the lead being tested is not under tension (e.g. remove the relevant fuse) and that any loads are disconnected.
2. Set the multimeter for measuring ohms.
3. Connect one test lead to a good ground and the other to the point to be tested.
4. Carefully jiggle the wiring harness and make sure the multimeter reading shows infinite resistance (OL) all the time.

Scheme 30

Scheme 31

Scheme 32

Scheme 33

Scheme 34

Scheme 35

Scheme 36

Scheme 37

1. When detaching connectors with locks, it is essential that the lock is released before the connector is detached. Ensure the connector locks properly when connecting. Example of some different connector types used in the car: 1.A. Pull out the slide to unlock the connector. After attaching the connector lock it by pressing in the slide. NOTE: Using a small screwdriver will help to unlock the connector. 1.B. Press in the lock tab to unlock the connector. Make sure the connector is locked properly when connecting. 1.C. Pull out the slide to unlock the connector. After attaching the connector lock it by pressing in the slide. 1.D. Press in the brace catch and push forward the brace. Push back the brace to lock the connector after connecting. NOTE: Make sure the brace is locked in the right position to ensure good contact between connectors. 1.E. Lift up the lock tab to unlock the connector. Make sure the connector is locked properly when connecting. 1.F. Press in the connector lock tab to release the brace. Release the connector slide while pushing the brace forward. NOTE: The connector may be damaged if too much force is used to push forward the brace without first releasing the slide. Push back the brace to lock the connector after connecting.
2. Ground yourself by touching the car body/engine before removing or fitting any of the connectors on the car's control modules.
3. Never pull the wiring harness when removing a connector.
4. Never touch the pins on the control module with your hands or clothes. IMPORTANT: Incorrect handing or the use of the wrong tool can damage the sleeves in the connector. Use a test cable (part no. 86 12 731) of the correct size to avoid damaging the sleeves in the connector.
5. When testing only probe tips intended for the purpose are to be used to avoid damaging the contacts. Use a test cable (part no. 86 12 731) of the right size.
6. Connectors may only be repaired when using specified special tools and spare parts.
7. The following connectors must not be repaired: Screened wires/coaxial cables (e.g. ESP sensor cable) Airbag system and pyrotechnical seat-belt tensioner system High tension cable (e.g. ignition system, xenon lamp).

Scheme 38

Scheme 39

1. Check for any contact problems in connections.
2. Check contacts, connectors and crimp connections with respect to oxidation, loose pins and pin clamping force. IMPORTANT: Incorrect handing or the use of the wrong tool can damage the sleeves in the connector. Use a test cable (part no. 86 12 731) of the correct size to avoid damaging the sleeves in the connector.
3. To check the connector clamping force, use a test cable with the right pin size (from kit 86 12 731). NOTE: Using a test cable that is too big will damage connector sleeves. Insert the test cable pin into the connector pin to feel the clamping force of the pins in question. Poor clamping force of the connector pins can cause bad contact. Also check that the engagement height of the pin is the same as the other pins in the connector. An engagement height that is too low could be an indication of a loose pin in the connector, which could cause bad contact.
4. Check wires and connections for open circuits.
5. Check wiring harness, connectors and ground connections.

Fault Diagnosis, Fault Codes

DIAGNOSTIC TROUBLE CODE (DTC) TABLE

Fault symptoms

TC/ESP OFF on

ABS lamp on

ABS, TCS or ESP inoperative

Before conducting fault diagnosis of the pressure sensor, the circuit for the brake light switch must first be checked. See BRAKE LIGHTS .

A pressure reading can be taken using the diagnostic tool. The value should be 0 when the pump is at rest and the brake pedal fully released.

Scheme 40

Fault symptom ESP-OFF lamp on

No ESP function

Lateral acceleration can be read using the diagnostic tool and should be approx. 0 m/s2 when the car is stationary.

ESP OFF lamp on

No ESP function

Yaw rate can be read using the diagnostic tool and should be approx. 0 when the car is stationary.

Scheme 41

The ESP OFF lamp is on when the fault is present but goes out when the fault disappears.

ESP OFF lamp on.

No ESP function.

This DTC indicates a fault in the ECM. Refer to fault diagnosis for the engine control module in question.

Fault diagnosis procedure is not available.

Scheme 42

ESP OFF indicator lamp on. ESP function missing.

Variant programming of ESP control module is carried out using the diagnostic tool.

1. Select "ESP"
2. Select "Programming"
3. Select "Configuration"

Program the correct brake size into the ESP control module.

Scheme 43

ESP OFF lamp on

No ESP function

The diagnostic tool can be used to read the value from the steering wheel angle sensor. This value should be 0°±6° for the straight-ahead position.

Scheme 44

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function

1. FL wheel speed sensor signal can be read using diagnostic tool. Select "Read values". Select "Wheel Speed Front Left".

Current wheel speed in km/h (mph) is displayed.

1. With the front of the car raised, the diagnostic tool should read approximately 5 km/h (3,1 mph) if the front left wheel is rotated by hand at about 1 rev./second.

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

1. FL wheel speed sensor signal can be read using diagnostic tool. Select "Read values". Select "Wheel Speed Front Left ".

Current wheel speed in km/h (mph) is displayed.

With the front of the car raised, the diagnostic tool should read approximately 5 km/h (3,1 mph) if the front left wheel is rotated by hand at about 1 rev./second.

1. For tracing electrical faults, the diagnostic tool can be used to take readings from the control module's wheel-sensor inputs. Select "Read values" Select "Wheel sensor output"

The reading is used to determine whether the control module has lost contact with any of the wheel sensors. If there is contact, the value should be approximately 3.4 V DC.

Defective contact front left approximately 2.7 V DC.

Scheme 45

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

1. A reading of the front right wheel speed sensor can be obtained with the diagnostic tool. Select "Read values". Select "Wheel Speed Front Right".

Current wheel speed in km/h (mph) is displayed.

1. With the front of the car raised, the diagnostic tool should read approximately 5 km/h (3,1 mph) if the front right wheel is rotated by hand at about 1 rev./second.

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

1. A reading of the front right wheel speed sensor can be obtained with the diagnostic tool. Select "Read values". Select "Wheel Speed Front Right".

Current wheel speed in km/h (mph) is displayed.

With the front of the car raised, the diagnostic tool should read approximately 5 km/h (3,1 mph) if the front right wheel is rotated by hand at about 1 rev./second.

1. For tracing electrical faults, the diagnostic tool can be used to take readings from the control module's wheel-sensor inputs. Select "Read values" Select "Wheel sensor output"

The reading is used to determine whether the control module has lost contact with any of the wheel sensors. If there is contact, the value should be approximately 3.4 V DC.

Defective contact front right approximately 0.8 V DC.

Scheme 46

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

1. A reading of the rear left wheel speed sensor can be obtained with the diagnostic tool. Select "Read values". Select "Wheel Speed Rear Left".

Current wheel speed in km/h (mph) is displayed.

1. With the rear wheels of the car raised, the diagnostic tool should read approximately 5 km/h (3,1 mph) if the rear left wheel is rotated by hand at about 1 rev./second.

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

1. A reading of the rear left wheel speed sensor can be obtained with the diagnostic tool. Select "Read values". Select "Wheel Speed Rear Left ".

Current wheel speed in km/h (mph) is displayed.

With the front of the car raised, the diagnostic tool should read approximately 5 km/h (3,1 mph) if the rear left wheel is rotated by hand at about 1 rev./second.

1. For tracing electrical faults, the diagnostic tool can be used to take readings from the control module's wheel-sensor inputs. Select "Read values" Select "Wheel sensor output"

The reading is used to determine whether the control module has lost contact with any of the wheel sensors. If there is contact, the value should be approximately 3.4 V DC.

Defective contact rear left approximately 1.4 V DC.

Scheme 47

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

1. A reading of the rear right wheel speed sensor can be obtained with the diagnostic tool. Select "Read values". Select "Wheel Speed Rear Right".

Current wheel speed in km/h (mph) is displayed.

1. With the rear wheels of the car raised, the diagnostic tool should read approximately 5 km/h (3.1 mph) if the rear right wheel is rotated by hand at about 1 rev/second.

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

1. A reading of the rear right wheel speed sensor can be obtained with the diagnostic tool. Select "Read values". Select "Wheel Speed Rear Right ".

Current wheel speed in km/h (mph) is displayed.

With the rear wheels of the car raised, the diagnostic tool should read approximately 5 km/h (3.1 mph) if the rear right wheel is rotated by hand at about 1 rev/second.

1. For tracing electrical faults, the diagnostic tool can be used to take readings from the control module's wheel-sensor inputs. Select "Read values" Select "Wheel sensor output"

The reading is used to determine whether the control module has lost contact with any of the wheel sensors. If there is contact, the value should be approximately 3.4 V DC.

Defective contact rear right approximately 2.1 V DC.

Scheme 48

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

1. The respective wheel speed sensor signal can be read using the diagnostic tool. Select "Read values". Select: "Wheel speed".

Current wheel speed in km/h (mph) is displayed.

Scheme 49

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ESP function.

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

The solenoid valves can be activated using the diagnostic tool.

1. Select "Activate".
2. Select "Valves".

The respective valve can then be selected in the sub-menu. The selected valve is activated for about 30 seconds at a frequency of 1 Hz.

ESP OFF lamp on

ESP lamp on

No ABS, TCS, ESP function

Further bus trouble codes may possibly be stored in the ECM and TCM. See fault diagnosis DIAGNOSTIC TOOL DISPLAYS "MISSING" FOR ONE/SEVERAL SYSTEMS (2006) DIAGNOSTIC TOOL DISPLAYS "MISSING" FOR ONE OR MORE SYSTEMS (2007) .

Fault diagnosis procedure is not available.

Scheme 50

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

ESP OFF lamp on

ESP lamp on

No ABS, TCS, ESP function.

Further trouble codes may be present in the ECM. See fault diagnosis Bus and diagnostic communication diagnostic trouble code P1625 .

Fault diagnosis procedure is not available.

Scheme 51

ESP OFF lamp on

No TCS/ESP function

Further trouble codes may be present in the ECM. See ECM fault diagnosis.

Fault diagnosis procedure is not available.

ESP OFF lamp on

No TCS, ESP function

Further trouble codes may be present in the ECM. See ECM fault diagnosis

Fault diagnosis procedure is not available.

ESP OFF lamp on

No TCS, ESP function

Further trouble codes may be present in the ECM. See ECM fault diagnosis.

Fault diagnosis procedure is not available.

ESP OFF lamp on

No ESP function

ESP OFF lamp on.

No ESP function.

This DTC indicates a fault in the TCM. See TCM fault diagnosis

Scheme 52

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

The solenoid valves can be activated using the diagnostic tool.

1. Select "Activate".
2. Select "Valves".

The respective valve can then be selected in the sub-menu. The selected valve is activated for about 30 seconds at a frequency of 1 Hz.

Change control module, see BEFORE CHANGING A CONTROL MODULE

Warning lamps for ESP and brakes are on as also is the central warning lamp.

ESP OFF warning lamp is on.

No ABS, TCS, ESP function.

The pump motor can be activated using the diagnostic tool.

1. Select "Activate".
2. Select "Pump motor".

Scheme 53

No fault symptoms.

The diagnostic tool can be used to determine the status of the brake light switch (Open/Closed).

1. Select "Read values".
2. Select "Brake light switch".

Scheme 54

No diagnostic communication.

See " SYSTEM OVERVIEW, BUS AND DIAGNOSTIC COMMUNICATION, PETROL (2006) or SYSTEM OVERVIEW, BUS AND DIAGNOSTICS COMMUNICATION, PETROL (2007) .

Fault diagnosis procedure is not available.

Scheme 55

It is not possible to turn off the ESP function with the switch.

When the ignition is switched ON, the ESP OFF warning lamp comes on for 10 seconds and then goes out.

No DTCs generated.

A reading of the ON/OFF status of the switch can be obtained with the diagnostic tool.

1. Select "Read values"
2. Select "ESP OFF Switch"

With the switch depressed the reading obtained should be ON.

If the lead is grounded for more than 10 seconds, the ESP control module will engage the ESP function and after that it will not be possible to disengage the function without first switching off the ignition and then switching it on again.

Scheme 56

Speedometer or cruise-control system not working.

Wheel speed can be read with the diagnostic tool from the ESP control module and the receiving control module.

See fault diagnosis in MAIN INSTRUMENT UNIT (2007) or MAIN INSTRUMENT UNIT (2006) " or "ECM".

Fault diagnosis procedure is not available.

Scheme 57

Fault symptom

No diagnostics communication with ABS or TC/ABS

First check the fuses for the ABS or TC/ABS and that the pin in data link connector for the ABS or TC/ABS has not been dislodged.

Even thought the TC/ABS is connected to the P-bus, diagnostics communication is via the K line.

Then check whether the ABS or TC/ABS is awake and allows diagnostics communication. If this is the case, check whether the diagnostics tool works in another car.

If no fault is found, rectify the communication cables between the ABS or TC/ABS and the diagnostic data link.