IWE System
IWE System
IWE System Vacuum Diagram
| Item | Description |
|---|---|
| 1 | Air cleaner outlet pipe |
| 2 | Brake booster |
| 3 | Intake manifold |
| 4 | IWE vacuum reservoir |
| 5 | IWE solenoid |
| 6 | IWE vacuum actuator LH |
| 7 | IWE vacuum actuator RH |
| 8 | Vacuum solenoid valve |
| 9 | Filter |
| 10 | Venturi |
| 11 | Aspirator assembly |
The IWE system consists of the following:
| 1 | IWE (spring-loaded vacuum hubs) |
|---|---|
| 2 | Vacuum hoses |
| 3 | IWE solenoid |
| 4 | Vacuum reservoir |
IWE components system:
VACUUM LINES AND VACUUM RESERVOIR
| Item | Description |
|---|---|
| 1 | Vacuum check valve. |
| 2 | Vacuum supply line. |
| 3 | Vacuum reservoir tank. |
| 4 | Vacuum control solenoid. |
| 5 | Vacuum output line. |
| 6 | IWE clutch ring. |
| 7 | IWE. |
| Item | Description |
|---|---|
| 1 | Vacuum check valve (3A788). |
| 2 | Vacuum supply line (Part of 3A788). |
| 3 | Vacuum reservoir tank (19A566). |
| 4 | Vacuum control solenoid (9H465). |
| 5 | Vacuum output line (7A785). |
The IWE system uses a vacuum solenoid and vacuum actuated hubs to engage or disengage the front wheel hubs from the front half shafts.
When the IWE4WD system is in 2H mode, the TCCM supplies a ground path to the IWE solenoid to apply engine vacuum to the thus disengaging the front hubs from the front half shafts. To maintain vacuum during all modes of engine operation, a one way vacuum check valve and a vacuum reservoir are positioned between the intake manifold and the IWE solenoid.
The TCCM has two startup strategies that affect IWE operation after initial key cycle:
When ambient temperature is below 32 F (0 deg. C), the IWE engage after initial key cycle and a driven gear is selected. The hubs stay engaged regardless of 4WD mode until 2 miles (3km) have been traveled above 6 mph (10 km/h). Once the set distance has been achieved, the IWE disengage (if the vehicle is in 2WD (2H)). Distance traveled resets only if the temperature is below calibrated threshold and another key cycle occurs or if customer shifts to Park (P) and back to a driven gear within the same key cycle. The TCCM uses this strategy to warm up the front axle in cold temperatures to improve driveline synchronization.
When ambient temperature is above 32 F (0 deg. C), the IWE engage after the initial key cycle and a driven gear is selected. The hubs stay engaged regardless of 4WD mode until 0.5 miles (0.8km) have been traveled above 6 mph (10 km/h). Engagement only occurs once per key cycle and is not reset when shifting between Park (P) and Drive (D). The TCCM uses this strategy to delay vacuum use until vacuum-intensive engine startup has completed and sufficient vacuum is available to fully disengage the IWE.