DTC P037A, P037B, or P0381 - Wait to Start Lamp Diagnosis

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5501849 DTC P037A, P037B, or P0381 - Wait to Start Lamp Diagnosis 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

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performanc
Ignition @ P16 Instrument Cluster	P0381	P0381	—	—
Control @ K20 Engine Control Module	P0381, P037A*	P0381, P037A	P037B	—
* Wait to Start Indicator = Always On

Circuit/System Description

Circuit	Description
Ignition @ P16 Instrument Cluster	Supplied from a fuse.
Control @ K20 Engine Control Module	The output circuit is switched to ground to activate the component.

	Component	Description
	K20 Engine Control Module	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

Component	Description
	sensors, interprets the data and adjusts the engine actuators accordingly.
P16 Instrument Cluster	The instrument cluster houses several displays and gauges to inform the driver about various parameters of the vehicle.

Conditions for Running the DTC M64 Starter Motor = Inactive Ignition = On Ignition Voltage = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC Control Circuit = Commanded state does not match the actual state — For greater than 1 s Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type B DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type B DTC Reference Information Schematic Reference Engine Controls Schematics Instrument Cluster 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
Perform the scan tool control function: Wait to Start Indicator » On and Off Verify the scan tool parameter: Wait to Start Indicator Control Circuit High Test Status = Not Run or Okay Wait to Start Indicator Control Circuit Low Test Status = Not Run or Okay Wait to Start Indicator Control Circuit Open Test Status = Not Run or Okay ⇒ If not the specified state Refer to: Circuit/System Testing ⇓ If the specified state
Perform the scan tool control function: Wait to Start Indicator » On and Off Verify the component turns On and Off: Wait to Start Indicator @ P16 Instrument Cluster ⇒ If the component does not turn On and Off Refer to: Circuit/System Testing ⇓ If the component turns On and Off
Perform the scan tool control function: Wait to Start Indicator » On Verify a condition does not exist with the component: Wait to Start Indicator @ P16 Instrument Cluster — Turns Off – Perform the action while monitoring the component: Wiggle the harness and connector: X1 @ K20 Engine Control Module ⇒ If a condition exists Repair as necessary » Wiring / Terminal(s) / Electrical Connector(s) ⇓ If no condition exists
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 that no DTCs are set. ⇒ If the DTC sets Refer to: Circuit/System Testing ⇓ If the DTC does not set
All OK. Circuit/System Testing
Verify the ignition fuse that supplies voltage to the component is not open: P16 Instrument Cluster ⇒ If the fuse is open 1.1. Ignition/Vehicle » Off 1.2. Disconnect the electrical connector: P16 Instrument Cluster 1.3. Test for infinite resistance between the test points: Ignition circuit terminal 8 & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇒ If infinite resistance » Replace the component: P16 Instrument Cluster ⇓ If the fuse is not open
Ignition/Vehicle » Off
Disconnect the appropriate electrical connector: K20 Engine Control Module
Ignition » On / Vehicle » In Service Mode
Verify the component works as specified: Wait to Start Indicator = Off ⇒ If the component does not work as specified 5.1. Ignition/Vehicle » Off 5.2. Test for infinite resistance between the test points: Control circuit terminal 28 X1 & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇒ If infinite resistance » Replace the component: P16 Instrument Cluster ⇓ If the component works as specified
Ignition/Vehicle » Off
Connect a 3 A fused jumper wire between the test points: Control circuit terminal 28 X1 & Ground
Ignition » On / Vehicle » In Service Mode
Verify the component works as specified: Wait to Start Indicator = On ⇒ If the component does not work as specified 9.1. Ignition/Vehicle » Off & Remove » Jumper wire(s) 9.2. Disconnect the appropriate electrical connector: P16 Instrument Cluster 9.3. Ignition » On / Vehicle » In Service Mode 9.4. Test for less than 1 V between the test points: Control circuit terminal 28 X1 @ Control module harness & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇓ If less than 1 V 9.5. Ignition/Vehicle » Off 9.6. Test for less than 2 Ω between the test points: Control circuit terminal 32 X1 @ 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 9.1. Test for less than 2 Ω between the test points: Ignition circuit terminal 8 @ Component harness & Output terminal @ Fuse ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: P16 Instrument Cluster ⇓ If the component works as specified
Replace the component: K20 Engine Control Module Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Instrument Cluster Replacement For control module replacement, programming, and setup refer to: Control Module References