AD25.40-W-6000-26A | WSK test of electrical system retarder stage switch |
| Scope of test | Measuring instrument/Test connection | Operation/Requirement | Specified value | Possible cause/Remedy | ||
1.0 | Retarder stage switch –//–, + HHT actual value | | Ignition:ON Retarder stage switch (S4):Stage 0 Read out HHT actual value 07 | If brake stage 1, 2, 3 or 4 is"ON" (shown against a black background): 1.1 If brake stage 1, 2, 3 and 4 is"OFF" (not shown against a black background): 1.3 | |||
1.1 | Retarder stage switch –//–, + TCC control module and retarder control module (Z44) Cables HHT actual value | | Ignition:OFF Disconnect plug from retarder stage switch (S4). Ignition:ON Read out HHT actual value 07 | If brake stage 1, 2, 3 and 4 is"OFF" (not shown against a black background): Replace S4 on an experimental basis If brake stage 1, 2, 3 and 4 is "ON" (shown against a black background): Check appropriate brake stage 1.2 | |||
1.2 | Retarder stage switch –//–, + TCC control module and retarder control module (Z44) Cables Brake stage 1 Brake stage 2 Brake stage 3 Brake stage 4 |
20 (or 25) 20 (or 25) 20 (or 25) 20 (or 25) |
S4 S4 S4 S4 |
10 22 9 8 | Ignition:OFF Connect Y-cable and socket box without control module to wiring harness. Ignition:ON | Value < 1 V: Replace Z44 on an experimental basis Value > 20 V: Cables (cable short-circuit or short-circuit to UB+). | |
1.3 | Retarder stage switch –//–, + HHT actual value | | Ignition:ON Read out HHT actual value Switch retarder stage switch (S4) through to stage 4 | If brake stage 1, 2, 3 and 4 is"ON" (shown against a black background): Check stage switch and connectors (loose contact) Replace TCC control module and retarder control module (Z44) on an experimental basis if the fault code appears again or cannot be erased. If brake stage 1, 2, 3 and 4 is"OFF" (shown against a black background): Check appropriate brake stage 1.4 | |||
1.4 | Retarder stage switch –//–, + Retarder stage switch (S4) Cable Brake stage 1 Brake stage 2 Brake stage 3 |
6/6 6/6 6/6 |
S4 S4 S4 |
6/4 6/3 6/2 | Ignition: OFF Disconnect plug on S4 Carry out measurement at socket housing of S4 (use suitable test cable from electrical connection set) Switch S4 to the defective stage | Value > 30 kΩ: Replace S4 on an experimental basis. Value < 5 Ω: Connector open-circuited Cable to stage switch open-circuited. | |