C2128
C2128-00-ECU RESET/RECOVERY OCCURRED
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Electro-Hydraulic Power Steering (EHPS) Pump assembly contains a control module, brushless electric motor, and hydraulic pump integrated into a single unit. The EHPS Pump draws power from the 12-Volt electrical system and provides the necessary flow and pressure to the steering gear to provide normal power steering. The EHPS Pump requires communication over the CAN C bus to function properly. The output flow of the EHPS Pump is varied as a function of Steering Wheel Rate (received from SAS) and Vehicle Speed (received from ABS Module) in order to provide the optimum flow of power steering fluid to the steering gear under all operating conditions. The EHPS Pump will start to provide steering assist when the Vehicle speed message greater than 5 km/h (3 mph) is received on CAN C. If the Vehicle Speed message is missing at vehicle startup, the EHPS Pump will not operate. If the Vehicle Speed message is lost during operation the EHPS pump will use a default vehicle speed of 85 km/h (59 mph) to calculate desired flow and as a result, steering effort will no longer be speed sensitive. If the Steering Wheel Position message is lost the EHPS Pump will use a default steering wheel rate of 230°/sec to calculate desired flow and as a result, steering effort may be higher on evasive steering maneuvers. The EHPS pump will resume normal operation automatically once any missing message or out of range condition noted above is restored to normal.
- When Monitored:
Once at each ignition cycle.
- Set Condition:
When the ignition is turned on, the Electro-Hydraulic Power Steering (EHPS) Module checks to see if the last shutdown occurred correctly. If it did not, this DTC will be set active for the remainder of the current key cycle. The EHPS Pump will run normally even if this DTC is active.
1. CHECK DTC-C2128-00-ECU RESET/RECOVERY OCCURRED
NOTE: Make sure the 12-Volt battery is fully charged before proceeding.
NOTE: This DTC must be active for the results of this test to be valid.
1. Ignition on, engine off.
2. With the scan tool, record and erase DTCs.
3. Cycle the ignition switch from off to on.
4. With the scan tool, read DTCs.
Does the scan tool display: DTC C2128-00-ECU RESET/RECOVERY OCCURRED?
Yes
- Replace and program the Electro-Hydraulic Power Steering (EHPS) Pump. Power Steering Pump - Removal.
- Perform the EHPS Verification Test. EHPS Verification Test.
No
- Go To 2
2. (A951) FUSED B(+) CIRCUIT OPEN OR HIGH RESISTANCE
1. Turn the ignition off to the lock position.
2. Disconnect the EHPS Module C2 harness connector.
NOTE: Wiggle test the wiring harness and electrical connectors while testing the circuit.
3. Using a 12-volt test light connected to ground, check the (A951) Fused B(+) circuit in the EHPS Module C2 harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Yes
- Go To 3
No
- Repair the (A951) Fused B(+) circuit for an open or high resistance.
- Perform the EHPS Verification Test. EHPS Verification Test.
3. (Z906) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
NOTE: Wiggle test the wiring harness and electrical connectors while testing the circuit.
1. Using a 12-volt test light connected to 12-volts, check the (Z906) Ground circuit in the EHPS Module C2 harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Yes
- Replace and program the Electro-Hydraulic Power Steering (EHPS) Pump. Power Steering Pump - Removal.
- Perform the EHPS Verification Test. EHPS Verification Test.
No
- Repair the (Z906) Ground circuit for an open or high resistance.
- Perform the EHPS Verification Test. EHPS Verification Test.