| Diagnosis and Testing Refer to Wiring Diagrams Section 417-01, for schematic and connector information. Special Tool(s) | | Terminal probe kit 29-011 A | General Equipment Worldwide Diagnostic System (WDS) Diagnosis and Testing NOTE:The central timer module (CTM) is part of the instrument cluster. NOTE:If the instrument cluster is changed, the new one must be reinitialised. For this purpose, the vehicle-specific data is read out of the module to be replaced using WDS and is transferred to the new module.
REFER to: Central Timer Module (CTM) (419-10 Multifunction Electronic Modules, Diagnosis and Testing).
NOTE:Before reading out the vehicle-specific data, remake all the electrical connections in the vehicle, so that communication between the module and WDS is ensured. - Verify the customer concern.
- Visually inspect for obvious signs of electrical damage.
NOTE:Ensure correct locking of wiring harness connector. Visual Inspection Chart | Electrical | - Fuse(s)
- Bulb(s)
- Electrical connector(s)
- Wiring harness
| - Resolve any obvious causes or concerns found during the visual inspection before carrying out any further tests.
- If the concern persists after the visual inspection, PERFORM a fault diagnosis on the central timer module (CTM) using WDS and RESOLVE the fault(s) displayed according to the fault description. CHECK the operation of the system.
- On a vehicle without stored fault(s), continue according to the Symptom Chart and the corresponding symptom.
- After checking or rectifying the fault(s) and finishing the work, READ OUT the fault memory in the central timer module (CTM) and DELETE any saved faults. After performing a road test and CHECKING the system, READ OUT the fault memories again.
WDS DTC table, central timer module (CTM) WDS DTC table, central timer module (CTM) | DTC | Description | Action | | B291B | Circuit of reversing lamp switch faulty (open circuit) | GO to Pinpoint Test D. | Symptom Chart Symptom Chart | Symptom | Possible Sources | Action | | Back-up lamp inoperative | * Fuse * Circuit(s) * Reversing lamp switch * Central junction box (CJB) | * | | Individual back-up lamp inoperative | * Circuit(s) * Left/right-hand rear lamp assembly | * | | Reversing lamps permanently lit | * Circuit(s) * Reversing lamp switch * Parking aid module * Instrument cluster | * | | Circuit of reversing lamp switch faulty (open circuit) | * Circuit(s) * Instrument cluster | * | Pinpoint Tests NOTE:Use a digital multimeter for all electrical measurements. | PINPOINT TEST A : BACK-UP LAMP INOPERATIVE | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | A1: CHECK FUSE F53/41 (10 A) (CJB) | | | 1 Ignition switch in position 0. | | | 2 Disconnect Fuse. - Vehicles built before 08/2006: F53 (10 A) (CJB)
- Vehicles built from 08/2006: F41 (10 A) (CJB)
| | | 3 CHECK Fuse. - Vehicles built before 08/2006: F53 (10 A) (CJB)
- Vehicles built from 08/2006: F41 (10 A) (CJB)
| | | Is the fuse OK? Yes No RENEW fuse F53/41 (10 A) (CJB) and CHECK the operation of the system. If the fuse blows again, LOCATE and RECTIFY the short using the Wiring Diagrams. CHECK the operation of the system. | | A2: CHECK THE VOLTAGE SUPPLY TO FUSE F53/41 (10A) (CJB) FOR OPEN CIRCUIT | | | 1 Connect Fuse. - Vehicles built before 08/2006: F53 (10 A) (CJB)
- Vehicles built from 08/2006: F41 (10 A) (CJB)
| | | 2 Ignition switch in position II. | | | 3 Measure the voltage between fuse: - Vehicles built before 08/2006: F53 (10 A) (CJB) and ground.
- Vehicles built from 08/2006: F41 (10 A) (CJB) and ground.
| | | Is battery voltage measured? Yes No LOCATE AND RECTIFY the break in the voltage supply of fuse F53/41 (10 A) (CJB) using the Wiring Diagrams. If necessary RENEW the CJB. CHECK the operation of the system. | | A3: CHECK VOLTAGE SUPPLY TO THE REVERSING LAMP SWITCH FOR OPEN CIRCUIT | | | 1 Ignition switch in position 0. | | | 2 Disconnect Reversing lamp switch from connector. - Vehicles built before 08/2006 with 1.8L Duratorq-TDCi (Kent) diesel engine: C862
| | | 3 Ignition switch in position II. | | | 4 Measure the voltage between reversing lamp switch: - Vehicles built before 08/2006 with 1.8L Duratorq-TDCi (Kent) diesel engine: Connector C862, pin 2, circuit 15-LG28 (GN/WH), wiring harness side and ground.
- All other vehicles: Connector C863, pin 2, circuit 15-LG28(B) (GN/WH), wiring harness side and ground.
| | | Is battery voltage measured? Yes No LOCATE and RECTIFY the break in the circuit between fuse F53/41 (CJB) and the reversing lamp switch using the Wiring Diagrams. CHECK the operation of the system. | | A4: CHECK REVERSING LAMP SWITCH | | | 1 Ignition switch in position 0. | | | | | | 2 Fused bridging cable (10A) at the reversing lamp switch: - Vehicles built before 08/2006 with 1.8L Duratorq-TDCi (Kent) diesel engine: connector C862, bridge between pin 2, circuit 15-LG28 (GN/WH) and pin 1, circuit 15S-LG3 (GN/YE), wiring harness side.
- All other vehicles: Connector C863, connect between pin 2, circuit 15-LG28(B) (GN/WH) and pin 1, circuit 15S-LG3 (GN/YE), wiring harness side.
| | | 3 Ignition switch in position II. | | | 4 Check the back-up lamps. | | | Are the back-up lamps on? Yes INSTALL A NEW reversing lamp switch. CHECK the operation of the system. No LOCATE and RECTIFY the break in circuit 15S-LG3 (GN/YE) between the reversing lamp switch and soldered connection S92 using the Wiring Diagrams. CHECK the operation of the system. | | PINPOINT TEST B : INDIVIDUAL BACK-UP LAMP INOPERATIVE | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | B1: DETERMINE INOPERATIVE REVERSING LAMP | | | 1 Ignition switch in position II. | | | 2 Engage reverse gear. | | | 3 CHECK the backup lamps. | | | Is the left-hand back-up lamp inoperative? Yes No Right-hand reversing lamp inoperative: GO to B4. | | B2: CHECK VOLTAGE SUPPLY TO LEFT-HAND REAR LAMP ASSEMBLY FOR OPEN CIRCUIT | NOTE:Reverse gear is still engaged. | | | 1 Ignition switch in position 0. | | | 2 Disconnect Left-hand rear lamp assembly from connector. - Vehicles without trailer socket: C474
- Vehicles with trailer socket: C474a
| | | 3 Ignition switch in position II. | | | 4 Measure the voltage between left-hand rear lamp assembly: - Vehicles without trailer socket: Connector C474, pin 4, circuit 15S-LG9 (GN/BK), wiring harness side and ground.
- Vehicles with trailer socket: Connector C474a, pin 4, circuit (GN), wiring harness side and ground.
| | | Is battery voltage measured? Yes No LOCATE and RECTIFY the break in the circuit between soldered connection S92 and the left-hand rear lamp assembly using the Wiring Diagrams. CHECK the operation of the system. | | B3: CHECK GROUND CONNECTION TO LEFT-HAND REAR LAMP ASSEMBLY FOR OPEN CIRCUIT | | | 1 Ignition switch in position 0. | | | 2 Measure the resistance between the left-hand rear lamp assembly: - Vehicles without trailer socket: Connector C474, pin 5, circuit 31-LF23 (BK), wiring harness side and ground.
- Vehicles with trailer socket: Connector C474a, pin 5, circuit (BN), wiring harness side and ground.
| | | Is a resistance of less than 2 Ohms registered? Yes CHECK and if necessary RENEW the left-hand rear lamp assembly. CHECK the operation of the system. No LOCATE and RECTIFY the break in the circuit between the left-hand rear lamp assembly and ground connection G46 using the Wiring Diagrams. CHECK the operation of the system. | | B4: CHECK VOLTAGE SUPPLY TO RIGHT-HAND REAR LAMP ASSEMBLY FOR OPEN CIRCUIT | NOTE:Reverse gear is still engaged. | | | 1 Ignition switch in position 0. | | | 2 Disconnect Right-hand rear lamp assembly from connector. - Vehicles without trailer socket: C475
- Vehicles with trailer socket: C475a
| | | 3 Ignition switch in position II. | | | 4 Measure the voltage between the right-hand rear lamp assembly: - Vehicles without trailer socket: Connector C475, pin 4, circuit 15S-LG16 (GN/OG), wiring harness side and ground.
- Vehicles with 7 pin trailer socket: Connector C475a, pin 4, circuit (GN), wiring harness side and ground.
- Vehicles with 13 pin trailer socket: Connector C475a, pin 4, circuit (VT/OG), wiring harness side and ground.
| | | Is battery voltage measured? Yes No LOCATE and RECTIFY the break in the circuit between soldered connection S92 and the right-hand rear lamp assembly using the Wiring Diagrams. CHECK the operation of the system. | | B5: CHECK THE GROUND CONNECTION TO THE RIGHT-HAND REAR LAMP ASSEMBLY FOR OPEN CIRCUIT | | | 1 Ignition switch in position 0. | | | 2 Measure the resistance between the right-hand rear lamp assembly: - Vehicles without trailer socket: Connector C475, pin 5, circuit 31-LF24 (BK), wiring harness side and ground.
- Vehicles with trailer socket: Connector C475a, pin 5, circuit (GN), wiring harness side and ground.
| | | Is a resistance of less than 2 Ohms registered? Yes CHECK and if necessary RENEW the right-hand rear lamp assembly. CHECK the operation of the system. No LOCATE and RECTIFY the break in the circuit between the right-hand rear lamp assembly and ground connection G47 using the Wiring Diagrams. CHECK the operation of the system. | | PINPOINT TEST C : REVERSING LAMPS PERMANENTLY LIT | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | C1: CHECK REVERSING LAMP SWITCH | | | 1 Ignition switch in position 0. | | | 2 Disconnect Reversing lamp switch from connector. - Vehicles built before 08/2006 with 1.8L Duratorq-TDCi (Kent) diesel engine: C862
| | | 3 Ignition switch in position II. | | | 4 CHECK the backup lamps. | | | Do the reversing lamps illuminate continuously? Yes - Vehicles built before 08/2006, without parking aid: LOCATE and RECTIFY the short to battery voltage in the circuits connected to soldered connection S92 using the Wiring Diagrams. (vehicles with trailer hitch, check trailer socket and RENEW it if necessary). CHECK the operation of the system. No INSTALL A NEW reversing lamp switch. CHECK the operation of the system. | | C2: ELIMINATE THE PARKING AID MODULE AS CAUSE FOR THE SHORT TO BATTERY VOLTAGE | | | 1 Ignition switch in position 0. | | | 2 Disconnect Fuse. - Vehicles built before 08/2006: F48 (7.5 A) (CJB)
- Vehicles built from 08/2006: F44 (7.5 A) (CJB)
| | | 3 Ignition switch in position II. | | | 4 CHECK the backup lamps. | | | Do the reversing lamps illuminate continuously? Yes - Vehicles built before 08/2006: LOCATE and RECTIFY the short to battery voltage in the circuits connected to soldered connection S92 using the Wiring Diagrams. Vehicles with trailer coupling, check trailer socket and RENEW if necessary. CHECK the operation of the system. - Vehicles built from 08/2006: GO to C3. No INSTALL a new parking aid module. CHECK the operation of the system. | | C3: ELIMINATE THE INSTRUMENT CLUSTER AS CAUSE FOR THE SHORT TO BATTERY VOLTAGE | | | 1 Ignition switch in position 0. | | | 2 Disconnect Fuse F37 (7.5 A) (CJB). | | | 3 Disconnect fuse F48 (7.5 A) (CJB). | | | 4 Disconnect Fuse F59 (7.5 A) (CJB). | | | 5 Ignition switch in position II. | | | 6 CHECK the backup lamps. | | | Do the reversing lamps illuminate continuously? Yes LOCATE and RECTIFY the short to battery voltage in the circuits connected to soldered connection S92 using the Wiring Diagrams. Vehicles with trailer coupling, check trailer socket and RENEW if necessary. CHECK the operation of the system. No INSTALL a new instrument cluster. CHECK the operation of the system. | | PINPOINT TEST D : CIRCUIT OF REVERSING LAMP SWITCH FAULTY (OPEN CIRCUIT) | | TEST CONDITIONS | DETAILS/RESULTS/ACTIONS | | D1: NARROW DOWN THE CAUSE OF THE FAULT | | | 1 Ignition switch in position II. | | | 2 Engage reverse gear. | | | 3 CHECK the backup lamps. | | | Are the back-up lamps on? Yes No | | D2: CHECK INSTRUMENT CLUSTER | | | 1 Ignition switch in position 0. | | | 2 Disconnect Instrument cluster from connector C809. | | | 3 Engage reverse gear. | | | 4 Measure the voltage between the instrument cluster, connector C809, pin 26, circuit 15S-GG11 (GN/BU), wiring harness side and ground. | | | Is battery voltage measured? Yes INSTALL a new instrument cluster. CHECK the operation of the system. No LOCATE and RECTIFY the break in the circuit between soldered connection S91 and the instrument cluster using the Wiring Diagrams. CHECK the operation of the system. | |
