Reference Information
Schematic Reference
Power Steering Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Power Steering System Description and Operation (Hydraulic Power Steering) or Power Steering System Description and Operation (EPS)
Electrical Information Reference
- «Circuit Testing»(ref-364488-S04114729552010063000000)
- «Connector Repairs»(ref-364488-S23771656832010063000000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
- «Wiring Repairs»(ref-364488-S17530456672010063000000)
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Verify that the DTC sets outside of the Conditions for Running and Setting. Since most occurrences of this DTC are caused by excessive driver inputs, review with the customer the conditions under which the DTC set.
- If the DTC set within the Conditions for Running and Setting, the power steering is operating as designed.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Schematic Reference
Power Steering Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Power Steering System Description and Operation (Hydraulic Power Steering) or Power Steering System Description and Operation (EPS)
Electrical Information Reference
- «Circuit Testing»(ref-364488-S04114729552010063000000)
- «Connector Repairs»(ref-364488-S23771656832010063000000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
- «Wiring Repairs»(ref-364488-S17530456672010063000000)
Scan Tool Reference
Control Module References for scan tool information
Engine running, then center the steering wheel, observe the scan tool Steering Wheel Position parameter, the reading should be 0 +/- 10 degrees.
- If not within the specified range, perform the steering position torque sensor calibration, and verify DTC C0460 is not set as current.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Power Steering Wiring Harness Extension Harness Replacement (HP2)»(ref-364521-S29343131072010063000000)
- «Power Steering Assist Motor Replacement»(ref-364521-S21884022962010063000000)
- «Control Module References»(ref-364489-S22329914082010063000000) for PSCM replacement, setup, and programming
Schematic Reference
Power Steering Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Power Steering System Description and Operation (Hydraulic Power Steering) or Power Steering System Description and Operation (EPS)
Electrical Information Reference
- «Circuit Testing»(ref-364488-S04114729552010063000000)
- «Connector Repairs»(ref-364488-S23771656832010063000000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
- «Wiring Repairs»(ref-364488-S17530456672010063000000)
Scan Tool Reference
Control Module References for scan tool information
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Power Steering Assist Motor Replacement»(ref-364521-S21884022962010063000000)
- «Control Module References»(ref-364489-S22329914082010063000000) for PSCM replacement, setup, and programming
Schematic Reference
Power Steering Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Power Steering System Description and Operation (Hydraulic Power Steering) or Power Steering System Description and Operation (EPS)
Electrical Information Reference
- «Circuit Testing»(ref-364488-S04114729552010063000000)
- «Connector Repairs»(ref-364488-S23771656832010063000000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
- «Wiring Repairs»(ref-364488-S17530456672010063000000)
Scan Tool Reference
Control Module References for scan tool information
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- «Power Steering Wiring Harness Extension Harness Replacement (HP2)»(ref-364521-S29343131072010063000000)
- «Steering Gear Replacement (Hydraulic Rack and Pinion)»(ref-364521-S01455014912010063000000) or «Steering Gear Replacement (Recirculating Ball Without LMM)»(ref-364521-S12670477072010063000000) or «Steering Gear Replacement (Two Mode Hybrid)»(ref-364521-S23943396982010063000000)
- «Control Module References»(ref-364489-S22329914082010063000000) for PSCM replacement, setup, and programming
Schematic Reference
Power Steering Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Power Steering System Description and Operation (Hydraulic Power Steering) or Power Steering System Description and Operation (EPS)
Electrical Information Reference
- «Circuit Testing»(ref-364488-S04114729552010063000000)
- «Connector Repairs»(ref-364488-S23771656832010063000000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
- «Wiring Repairs»(ref-364488-S17530456672010063000000)
Scan Tool Reference
Control Module References for scan tool information
Verify that no DTCs are set in the ECM or APM.
- If DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-364486-S07394808542010063000000) .
Schematic Reference
Power Steering Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Power Steering System Description and Operation (Hydraulic Power Steering) or Power Steering System Description and Operation (EPS)
Electrical Information Reference
- «Circuit Testing»(ref-364488-S04114729552010063000000)
- «Connector Repairs»(ref-364488-S23771656832010063000000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
- «Wiring Repairs»(ref-364488-S17530456672010063000000)
Scan Tool Reference
Control Module References for scan tool information
| WARNING | Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death. |
| IMPORTANT | Verify the motor connector is securely connected and not loose. |
Verify that DTC C056D is not set.
- If the DTC is set, replace the PSCM.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for PSCM replacement, setup, and programming
Schematic Reference
Power Steering Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Power Steering System Description and Operation (Hydraulic Power Steering) or Power Steering System Description and Operation (EPS)
Electrical Information Reference
- «Circuit Testing»(ref-364488-S04114729552010063000000)
- «Connector Repairs»(ref-364488-S23771656832010063000000)
- «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
- «Wiring Repairs»(ref-364488-S17530456672010063000000)
Scan Tool Reference
Control Module References for scan tool information
- Verify DTC C056E 42 is not set. If DTC C056E 42 is set, perform the PSCM programming and setup procedures. If DTC C056E 42 resets, replace the PSCM.
- Verify DTC C056E 4B is not set. If DTC C056E 4B is set, perform the steering position/torque sensor calibration. If DTC C056E 4B resets, replace the PSCM.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for PSCM replacement, setup, and programming
| IMPORTANT | Review the system description and operation in order to familiarize yourself with the system functions. Refer to Power Steering System Description and Operation (Hydraulic Power Steering) or Power Steering System Description and Operation (EPS) . |
Procedure
Note. If fluid is found on a manual steering gear or on an electronic power steering gear, do not replace steering gear. Vehicles equipped with these systems do not use hydraulic power steering fluid. The fluid may be assembly fluid or another system fluid. Clean the components and identify the sources of the leaks before attempting to repair or replace any power steering components. Clearly mark all locations of leaks with paint, marker, or equivalent for warranty identification and engineering root cause analysis.
Some customers may comment on a fluid LEAK or NOISY power steering pump. Upon inspection, the technician may find power steering fluid leaking from the hydraulic power steering system. Use the following inspection procedure in order to diagnose the source of the leak and take appropriate action to correct the condition.
- Inspect the fluid level in the power steering fluid reservoir. Refer to «Checking and Adding Power Steering Fluid (Without Hydroboost)»(ref-364521-S15192182822010063000000) or «Checking and Adding Power Steering Fluid (With Hydroboost)»(ref-364521-S42283808782010063000000) . If the fluid level is NOT low, a careful analysis of the condition is necessary to confirm that the type of fluid is actually power steering fluid.
- Visually inspect the power steering system and components where the fluid has accumulated.
- Use a clean towel or a rag in order to completely clean off all residual fluid from the power steering components.
- Add 30 cc (1 oz) of GE-28431-6: dye to the power steering fluid.
- Start the vehicle and warm the steering system by turning to the left steering stop and to the right steering stop 10 times with the weight of the vehicle on the front tires.
- Turn vehicle engine OFF.
- Shine a black light on the area where the residual fluid accumulated. Identify the sources of the leaks. If equipped with hydroboost, refer to «Hydraulic Brake Booster Leak Inspection»(ref-364510-S10296124822010063000000) .
- Mark all locations of leaks with paint, marker, or equivalent.
- Repair or replace all affected components.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review the Power Steering System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Power Steering System |
| 2 | Verify that a rattle, clunk or shudder noise is present. Is a rattle, clunk or shudder noise present? | Go to Step 3 | System OK |
| 3 | Inspect the power steering hoses for proper routing and clearance. Is the routing or clearance of the power steering hoses incorrect? | Go to Step 11 | Go to Step 4 |
| 4 | Inspect the engine drive belt for cracking or excessive wear. Refer to Drive Belt Falls Off and Excessive Wear Diagnosis . Is the drive belt cracked or excessively worn? | Go to Step 12 | Go to Step 5 |
| 5 | Inspect the power steering pump pulley for damage. Is the power steering pump pulley damaged? | Go to Step 13 | Go to Step 6 |
| 6 | Inspect the power steering pump, the power steering mounting bracket, and the brace for the proper installation. Refer to Power Steering Pump Replacement (4.8L, 5.3L, 6.0L, and 6.2L) . Is the power steering pump installation incorrect? | Go to Step 14 | Go to Step 7 |
| 7 | Inspect the power steering gear for the proper installation. Refer to Steering Gear Replacement (Hydraulic Rack and Pinion) or Steering Gear Replacement (Recirculating Ball Without LMM) . Is the power steering gear installation incorrect? | Go to Step 15 | Go to Step 8 |
| 8 | Inspect the steering linkage. Refer to Steering Linkage Inspection . Is the steering linkage worn? | Go to Step 16 | Go to Step 9 |
| 9 | Inspect the suspension. Is the suspension worn? | Go to Step 17 | Go to Step 10 |
| 10 | Inspect the intermediate shaft. Is the intermediate shaft worn? | Go to Step 18 | Go to Step 3 |
| 11 | Adjust or replace the hoses. Refer to the appropriate procedure: Power Steering Fluid Cooler Replacement (Without Hydroboost) or Power Steering Fluid Cooler Replacement (With Hydroboost) Power Steering Gear Inlet Pipe/Hose Replacement (Gas With Hydroboost) or Power Steering Gear Inlet Pipe/Hose Replacement (Gas Without Hydroboost) Power Brake Booster Inlet Hose Replacement Power Brake Booster Outlet Hose Replacement Did you complete the repair? | Go to Step 19 | |
| 12 | Replace the engine drive belt. Refer to Drive Belt Replacement - Accessory . Did you complete the repair? | Go to Step 19 | |
| 13 | Replace the power steering pump pulley. Refer to Power Steering Pump Pulley Replacement (4.3L, 4.8L, 5.3L, 6.0L, 6.2L) . Did you complete the repair? | Go to Step 19 | |
| 14 | Install the power steering pump correctly. Refer to Power Steering Pump Replacement (4.8L, 5.3L, 6.0L, and 6.2L) . Did you complete the repair? | Go to Step 19 | |
| 15 | Install the power steering gear correctly. Refer to Steering Gear Replacement (Hydraulic Rack and Pinion) or Steering Gear Replacement (Recirculating Ball Without LMM) . Did you complete the repair? | Go to Step 19 | |
| 16 | Replace the worn steering linkage. Refer to Steering Linkage Inspection . Did you complete the repair? | Go to Step 19 | |
| 17 | Replace the worn suspension components. Did you complete the repair? | Go to Step 19 | |
| 18 | Replace the intermediate shaft. Refer to Upper Intermediate Steering Shaft Replacement or to Steering Shaft Coupling Replacement . Did you complete the repair? | Go to Step 19 | |
| 19 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review the Power Steering System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Power Steering System |
| 2 | Verify that a rattle, clunk or shudder noise is present. Is a rattle, clunk or shudder noise present? | Go to Step 3 | System OK |
| 3 | Inspect the power steering gear bushings for wear or damage. Are the power steering gear bushings worn or damaged? | Go to Step 8 | Go to Step 4 |
| 4 | Inspect the power steering gear for proper installation. Refer to Steering Gear Replacement (Hydraulic Rack and Pinion) or Steering Gear Replacement (Recirculating Ball Without LMM) or Steering Gear Replacement (Two Mode Hybrid) . Is the power steering gear installation correct? | Go to Step 5 | Go to Step 9 |
| 5 | Inspect the steering linkage. Refer to Steering Linkage Inner Tie Rod Inspection and to Steering Linkage Outer Tie Rod Inspection . Did you find and correct the condition? | Go to Step 12 | Go to Step 6 |
| 6 | Inspect the suspension. Is the suspension worn? | Go to Step 10 | Go to Step 7 |
| 7 | Inspect the intermediate shaft. Is the intermediate shaft worn? | Go to Step 11 | Go to Step 3 |
| 8 | Replace the power steering gear. Refer to Steering Gear Replacement (Hydraulic Rack and Pinion) or Steering Gear Replacement (Recirculating Ball Without LMM) or Steering Gear Replacement (Two Mode Hybrid) . Did you complete the repair? | Go to Step 12 | |
| 9 | Install the power steering gear correctly. Refer to Steering Gear Replacement (Hydraulic Rack and Pinion) or Steering Gear Replacement (Recirculating Ball Without LMM) or Steering Gear Replacement (Two Mode Hybrid) . Did you complete the repair? | Go to Step 12 | |
| 10 | Replace the worn suspension components. Did you complete the repair? | Go to Step 12 | |
| 11 | Replace the intermediate shaft. Refer to Upper Intermediate Steering Shaft Replacement or to Steering Shaft Coupling Replacement . Did you complete the repair? | Go to Step 12 | |
| 12 | Operate the system in order to verify the repair. Did you correct the condition? | Go to System OK | Go to Step 3 |
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review the Power Steering System General Description and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Power Steering System |
| 2 | Verify that a whine or growl noise is present. Is a whine or growl noise present? | Go to Step 3 | System OK |
| 3 | Inspect the power steering gear for looseness and/or worn bushings. Is the steering gear loose or the bushings worn? | Go to Step 6 | Go to Step 4 |
| 4 | Inspect the power steering assist motor for a whine or growl noise using chassis ear J 39570 . Is the noise present at the power steering motor? | Go to Step 7 | Go to Step 5 |
| 5 | Inspect the power steering gear for a whine or growl noise using chassis ear J 39570 . Is the noise present at the power steering gear? | Go to Step 8 | Go to Step 3 |
| 6 | Tighten the power steering gear fasteners or replace the power steering gear due to worn bushings. Refer to the appropriate procedure(s): Fastener Tightening Specifications Steering Gear Replacement (Hydraulic Rack and Pinion) or Steering Gear Replacement (Recirculating Ball Without LMM) or Steering Gear Replacement (Two Mode Hybrid) Did you complete the repair? | Go to Step 9 | |
| 7 | Replace the power steering assist motor. Refer to Power Steering Assist Motor Replacement . Did you complete the repair? | Go to Step 9 | |
| 8 | Replace the power steering gear. Refer to Steering Gear Replacement (Hydraulic Rack and Pinion) or Steering Gear Replacement (Recirculating Ball Without LMM) or Steering Gear Replacement (Two Mode Hybrid) . Did you complete the repair? | Go to Step 9 | |
| 9 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review the Power Steering System General Description and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Power Steering System |
| 2 | Verify that a whine or growl noise is present. Is a whine or growl noise present? | Go to Step 3 | System OK |
| 3 | Inspect the power steering fluid for the following indications of contamination: Milky fluid - water Brown fluid - burnt Debris in fluid - plastic or dirt Is the fluid free of contamination? | Go to Step 5 | Go to Step 4 |
| 4 | Flush the power steering system. Refer to Power Steering System Bleeding . Did you complete the procedure? | Go to Step 11 | Go to Step 5 |
| 5 | Inspect the power steering gear for a whine or growl noise using J 39570 . Is the noise present at the power steering gear? | Go to Step 8 | Go to Step 6 |
| 6 | Inspect the power steering pump for a whine or growl noise using J 39570 . Is the noise present at the power steering pump? | Go to Step 9 | Go to Step 7 |
| 7 | Inspect the power steering hoses for a whine or growl noise using J 39570 . Is the noise present at the power steering hoses? | Go to Step 10 | Go to Step 2 |
| 8 | Replace the power steering gear. Refer to Steering Gear Replacement (Hydraulic Rack and Pinion) or Steering Gear Replacement (Recirculating Ball Without LMM) or Steering Gear Replacement (Two Mode Hybrid) . Did you complete the repair? | Go to Step 11 | |
| 9 | Replace the power steering pump. Refer to Power Steering Pump Replacement (4.8L, 5.3L, 6.0L, and 6.2L) . Did you complete the repair? | Go to Step 11 | |
| 10 | Adjust the routing of the power steering hoses. Did you complete the repair? | Go to Step 11 | |
| 11 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
Poor Return of Steering Wheel
| Step | Action | Yes | No |
|---|---|---|---|
| DEFINITION: After completing a turn, extra steering input is required for the steering wheel to return to center. | |||
| 1 | Did you review the Power Steering System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Power Steering System |
| 2 | Verify that poor return of the steering wheel is present. Does the system operate normally? | System OK | Go to Step 3 |
| 3 | Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle . Lubricate the tie rod ends and ball joints, if applicable. Inspect the suspension system for worn or damaged components. Repair as necessary. Did you find and correct the condition? | Go to Step 12 | Go to Step 4 |
| 4 | Rotate the steering wheel ONE revolution in both directions. Rotate the steering wheel back to the original position. Was the steering wheel abnormally difficult to rotate in either direction? | Go to Step 5 | Go to Step 10 |
| 5 | NOTE: Position the wheels straight ahead. Do NOT rotate the steering wheel more than one complete revolution from center. Disconnect the intermediate shaft from the steering column. Note the position of the steering wheel and rotate the steering wheel ONE revolution in both directions. Rotate the steering wheel back to the original position. Was the steering wheel abnormally difficult to rotate in either direction? | Go to Step 11 | Go to Step 6 |
| 6 | Inspect the intermediate shaft for stiff or loose joints. Repair or replace as necessary. Did you find and complete the repair? | Go to Step 12 | Go to Step 7 |
| 7 | Remove the front tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation . Disconnect both outer tie rod ends from the steering knuckles. Use your hands in order to move the tie rod end studs. If abnormally difficult to move, replace the tie rod end. If equipped with recirculating ball steering, ensure that idler and pitman arm joints are not to stiff. Repair as necessary. Did you find and complete the repair? | Go to Step 12 | Go to Step 8 |
| 8 | Use your hands to rotate the steering knuckle inboard and outboard in order to inspect for a binding strut bearings, ball joints, or axle. Repair or replace any abnormally stiff or loose components. Did you find and complete the repair? | Go to Step 12 | Go to Step 9 |
| 9 | Inspect for binding in the steering gear. If a binding is present, repair or replace the steering gear. Did you find and complete the repair? | Go to Step 12 | Go to Step 10 |
| 10 | Inspect the wheel alignment and adjust as necessary. Refer to Wheel Alignment Measurement . Did you find and complete the repair? | Go to Step 12 | |
| 11 | Inspect the steering column for a binding. If a binding is present, repair or replace the steering column as necessary. Did you find and complete the repair? | Go to Step 12 | |
| 12 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | |
| NOTE |
|---|
| Position the wheels straight ahead. Do NOT rotate the steering wheel more than one complete revolution from center. |
Steering Effort Too Easy in One or Both Directions
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review the Power Steering System Description and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Power Steering System |
| 2 | Verify that the steering effort is too easy in one or both directions. Does the system operate normally? | System OK | Go to Step 3 |
| 3 | Perform the power steering test procedure. Refer to Power Steering System Test . Did you complete the procedure? | Go to Step 4 | |
| 4 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
Steering Effort Hard in One or Both Directions (Standard)
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review the Power Steering System General Description and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Power Steering System |
| 2 | Verify that the steering effort is hard in one or both directions. Does the system operate normally? | System OK | Go to Step 3 |
| 3 | Perform the power steering test procedure. Refer to Power Steering System Test . Did you complete the procedure? | Go to Step 4 | |
| 4 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
Steering Effort Hard in One or Both Directions (HP2)
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review the Power Steering System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Power Steering System |
| 2 | Verify the steering effort is hard in one or both directions. Is the steering effort hard in one or both directions? | Go to Step 3 | System OK |
| 3 | NOTE: Position the front wheels straight ahead. DO NOT rotate the steering wheel more than one complete revolution either way from the center position. Disconnect the steering shaft coupling from the steering gear. Refer to Steering Shaft Coupling Replacement . Rotate the steering wheel in both directions. Does the condition still exist? | Go to Step 7 | Go to Step 4 |
| 4 | Reconnect the steering shaft coupling to the steering gear. Refer to Steering Shaft Coupling Replacement . Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle . Disconnect the outer tie rods from the steering knuckles. Refer to Steering Linkage Outer Tie Rod Replacement . Rotate the wheels in both directions. Does the condition still exist? | Go to Step 8 | Go to Step 5 |
| 5 | Reconnect the outer tie rods to the steering knuckles. Refer to Steering Linkage Outer Tie Rod Replacement . Disconnect the power steering assist motor from the power steering gear and support the motor on the frame. Refer to Power Steering Assist Motor Replacement . Rotate the steering wheel in both directions. Does the condition still exist? | Go to Step 9 | Go to Step 6 |
| 6 | Replace the power steering assist motor. refer to Power Steering Assist Motor Replacement . Did you complete the repair? | Go to Step 11 | |
| 7 | Inspect the following components for binding. If binding is present then replace the worn or damaged component: Upper intermediate steering shaft-Refer to Upper Intermediate Steering Shaft Replacement . Steering shaft coupling-Refer to Steering Shaft Coupling Replacement . Steering column upper bearing-Refer to Steering Shaft Upper Bearing Replacement . Steering column lower bearing-Refer to Steering Shaft Lower Bearing Replacement . Steering column tilt head-Refer to Steering Column Replacement (HP2) . Did you complete the repair? | Go to Step 11 | |
| 8 | Inspect the following components for binding. If binding is present then replace the worn or damaged components: Upper ball joints-Refer to Upper Control Arm Replacement (1500) or Upper Control Arm Replacement (2500) . Lower ball joints-Refer to Lower Control Arm Ball Joint Replacement (1500 ) or Lower Control Arm Ball Joint Replacement (2500, 3500 ) . Did you complete the repair? | Go to Step 11 | |
| 9 | Inspect the following components for binding. If binding is present then replace the worn or damaged component: Outer tie rods-Refer to Steering Linkage Outer Tie Rod Replacement . Inner tie rods-Refer to Steering Linkage Inner Tie Rod Replacement (Two Mode Hybrid) or Steering Linkage Inner Tie Rod Replacement (Standard) . Did you complete the repair? | Go to Step 11 | Go to Step 10 |
| 10 | Replace the steering gear. Refer to Steering Gear Replacement (Hydraulic Rack and Pinion) or Steering Gear Replacement (Recirculating Ball Without LMM) or Steering Gear Replacement (Two Mode Hybrid) . Did you complete the repair? | Go to Step 11 | |
| 11 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 4 |
| NOTE |
|---|
| Position the front wheels straight ahead. DO NOT rotate the steering wheel more than one complete revolution either way from the center position. |
Power Steering Control Module
The accessory power module (APM) provides a shielded, 42-volt circuit to the power steering control module (PSCM) to drive the power steering motor. The PSCM also uses the 12-volt battery circuit to power the module electronics. The normal operation voltage range the APM provides to the PSCM is between 40-44 volts. The APM is not capable of handling more than 58 volts. The dynamic brake circuit of the PSCM is used to keep the reverse motor voltage of the electric power steering system below 58 volts, and will start to consume the surplus voltage if the 42-volt circuit rises in a range between 50-58 volts.
The APM is also monitored by the hybrid control module (HCM) to detect overheating. If overheating of the APM is detected, the HCM sends a serial data message to the PSCM via the serial data gateway module as the power output to the PSCM is reduced until the APM returns to a normal operating temperature. The PSCM will reduce power assist according to the reduced output power provided by the APM, and will return to full steering assist when the APM returns to normal operating temperature.
The PSCM uses a combination of commanded motor voltage and current levels to calculate an estimated power steering system temperature. Neither the PSCM nor the power steering motor are designed to handle around 60-amps continuously and will enter into overload protection mode if the system is exposed to exclusive static steering conditions. If the steering wheel is turned to its maximum rotation point and held at this position for an extended period of time, the PSCM will reduce the amount of current commanded to the power steering motor, which reduces the amount of steering assist as well as system temperature. The PSCM has the ability to detect malfunctions within the power steering system. Any malfunction detected will cause the SERVICE POWER STEERING message to be displayed on the driver information center (DIC).
Power Steering Motor
The power steering control module (PSCM) responds to the change in the sinusoidal voltage signals of the torque and motor rotational sensors by commanding current to the power steering motor. The motor is attached to the base of the steering gear housing and assists the steering gear pinion to maneuver the rack from left to right according to turning the steering wheel. The 42-volt circuit from the APM supplies power to the pulse width modulated (PWM) motor drive circuit. The motor is a brushless, 3 phase motor with a rated maximum phase current of 40-amps rms.