DTC P0475, P0478, P10C0, P10EB, P2B98, or P2B99

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5471205 Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC P0475 Exhaust Pressure Regulator Valve Control Circuit DTC P0478 Exhaust Pressure Regulator Valve Control Circuit High DTC P10C0 Exhaust Pressure Regulator Valve Control Circuit Shorted DTC P10EB Exhaust Pressure Regulator Valve Driver Current Too High DTC P2B98 Exhaust Pressure Regulator Valve Supply Voltage Circuit Low DTC P2B99 Exhaust Pressure Regulator Valve Driver Temperature Too High Circuit/System Description For an overview of the component/system, refer to: Exhaust Gas Recirculation (EGR) System Description

Circuit	Description
Control — Terminal 4	The output circuit is switched from ground to 12 V to activate the component. The output is PWM controlled.
Control — Terminal 5	The output circuit is switched from ground to 12 V to activate the component. The output is PWM controlled.

	Component	Description
	K20 Engine Control Module	The control module contains a microprocessor used to process input data to control outputs. The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.
	M122 Exhaust Pressure Control Valve Actuator	The assembly has several functions:

Component	Description
	The component is actuated by a bidirectional DC motor. The component contains a contactless inductive position sensor. A fixed transmitter coil excites a movable rotor, which in turn induces a current in a fixed receiver coil. The current varies with the angle of the rotor. Electronics inside the sensor convert the current into digital data which is transmitted via a serial data circuit to the control module.

Component

Description

The component is actuated by a bidirectional DC motor. The component contains a contactless inductive position sensor. A fixed transmitter coil excites a movable rotor, which in turn induces a current in a fixed receiver coil. The current varies with the angle of the rotor. Electronics inside the sensor convert the current into digital data which is transmitted via a serial data circuit to the control module.

Conditions for Running the DTC P0475, P0478, P10C0, P10EB M64 Starter = Inactive { P0475 } M122 Exhaust Pressure Control Valve Actuator = Off { P0478, P10C0, P10EB } M122 Exhaust Pressure Control Valve Actuator = On Ignition and Start Signal = Greater than 11 V { P0475 } Valve @ M122 Exhaust Pressure Control Valve Actuator ≠ Full Open Frequency the DTC runs = Continuously — After the running conditions are met P2B98, P2B99 M64 Starter = Inactive Ignition and Start Signal = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC P0475, P0478 Control Circuit = Commanded state does not match the actual state — For greater than 4 s P10C0 Control Circuit — Terminal 4 & 5 = Short between the circuits — For greater than 4 s P10EB Control module K20 detects: High Current @ Control Circuit — For greater than 4 s P2B98 Exhaust Pressure Regulator Valve = Supply Voltage Circuit Low Voltage — For greater than 4 s P2B99 Motor Temperature @ Exhaust Pressure Regulator Valve = High Temperature — For greater than 4 s Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type A DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type A DTC Reference Information Schematic Reference Engine Controls Schematics Connector End View Reference Master Electrical Component List Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs DTC Type Reference Powertrain Diagnostic Trouble Code (DTC) Type Definitions Scan Tool Reference Control Module References Circuit/System Verification

Ignition » On / Vehicle » In Service Mode
Verify DTC P048D, P048E, U0650 is not set. ⇒ If any DTC is set Refer to: DTC P048D, P048E, or U0650 ⇓ If none of the DTCs are set
Perform the scan tool control function: Exhaust Pressure Regulator Valve Position » Command the component to the minimum position/speed & Release Control Verify the scan tool parameter: Exhaust Pressure Regulator Valve Control Circuit High Test Status = Not Run or Okay Exhaust Pressure Regulator Valve Control Circuit Low Test Status = Not Run or Okay Exhaust Pressure Regulator Valve Control Circuit Open Test Status = Not Run or Okay Exhaust Pressure Regulator Valve Control Circuit Shorted Test Status = Not Run or Okay ⇒ If not the specified state Refer to: Circuit/System Testing ⇓ If the specified state
Engine » Idling — At normal operating temperature
Perform the scan tool control function: Exhaust Pressure Regulator Valve Position » Command the component to the minimum position/speed Verify the scan tool parameter: Exhaust Pressure Regulator Valve Position = The parameter value should change. ⇒ If the parameter value does not change Refer to: Circuit/System Testing ⇓ If the parameter value changes
Perform the scan tool control function: Exhaust Pressure Regulator Valve Position » Command the component to the minimum position/speed Verify the scan tool parameter: Exhaust Pressure Regulator Valve Position = The parameter value should not change – Perform the action while monitoring the parameter: Wiggle the harness and connector: K20 Engine Control Module Wiggle the harness and connector: M122 Exhaust Pressure Control Valve Actuator ⇒ If the parameter value changes Repair as necessary » Wiring / Terminal(s) / Electrical Connector(s) ⇓ If the parameter value does not change
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. Verify the DTC does not set. ⇒ If the DTC sets Refer to: Circuit/System Testing ⇓ If the DTC is not set
All OK. Circuit/System Testing
Ignition/Vehicle » Off
Disconnect the electrical connector: M122 Exhaust Pressure Control Valve Actuator
Ignition » On / Vehicle » In Service Mode
Test for 8 to 10 V between the test points: Control circuit terminal 4 & Ground Control circuit terminal 5 & Ground ⇒ If less than 8 V 4.1. Ignition/Vehicle » Off 4.2. Disconnect the appropriate electrical connector: K20 Engine Control Module 4.3. Test for infinite resistance between the test points: Control circuit terminal 4 @ Component harness & Ground Control circuit terminal 5 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance 4.4. Test for infinite resistance between the test points: Control circuit terminal 4 & Control circuit terminal 5 @ Component harness ⇒ If less than infinite resistance » Repair the short between the circuits. ⇓ If infinite resistance 4.5. Test for less than 2 Ω between the test points: Control circuit terminal 4 @ Component harness & The other end of the circuit @ Control module harness Control circuit terminal 5 @ Component harness & The other end of the circuit @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module ⇒ If greater than 10 V 4.1. Ignition/Vehicle » Off 4.2. Disconnect the appropriate electrical connector: K20 Engine Control Module 4.3. Ignition » On / Vehicle » In Service Mode 4.4. Test for less than 1 V between the test points: Control circuit terminal 4 @ Component harness & Ground Control circuit terminal 5 @ Component harness & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇒ If less than 1 V » Replace the component: K20 Engine Control Module ⇓ If between 8 and 10 V
Connect a test lamp between the test points: Control circuit terminal 4 & Control circuit terminal 5
Perform the scan tool control function: Exhaust Pressure Regulator Valve » Command the component to the maximum position/speed Verify the test lamp turns On. ⇒ If the test lamp does not turn On 6.1. Ignition/Vehicle » Off & Remove » Test lamp 6.2. Disconnect the appropriate electrical connector: K20 Engine Control Module 6.3. Test for less than 2 Ω between the test points: Control circuit terminal 4 @ Component harness & The other end of the circuit @ Control module harness Control circuit terminal 5 @ Component harness & The other end of the circuit @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K20 Engine Control Module ⇓ If the test lamp turns On
Test or replace the component: M122 Exhaust Pressure Control Valve Actuator Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Exhaust Back Pressure Valve Replacement — M122 Exhaust Pressure Control Valve Actuator For control module replacement, programming, and setup refer to: Control Module References