2010 Cadillac CTS Sedan AWD V6-3.6L Page 935
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P050D
- Cold Start Rough Idle
Circuit/System Description
During a cold start, the engine control module (ECM) commands dual-pulse mode during Open Loop operation to improve cold start emissions. In
dual-pulse mode, the injectors are energized twice during each injection event. As with misfire diagnosis, in dual-pulse mode the ECM monitors the
crankshaft position sensor and the camshaft position sensors to calculate crankshaft rotation speed. In normal operation, optimum fuel delivery
during dual-pulse mode produces a steady crankshaft rotation speed. If the variations exceed a calibrated value, the code will be set.
Conditions for Running the DTC
* DTCs P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0089, P0090-P0092, P00C6, P00C8,
P00C9, P00CA, P0101-P0103, P0106-P0108, P0112-P0114, P0116-P0118, P0121-P0123, P0128, P0192, P0193, P0201-P0206, P0222,
P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0315, P0335, P0336, P0351-P0356,
P0627-P0629, P069E, P0716, P0717, P0722, P0723, P0850-P0852, P1248, P1249, P124A, P124B, P124C, P124D, P1258, P135A, P135B,
P150C, P163A, P1762, P1763, P1915, P2122, P2123, P2127, P2128, P2135, P2138, P2147, P2148, P2150, P2151, P2153, P2154, P2156,
P2157, P216B, P216C, P216E, P216F, P228C, P228D, U0109 are not set.
* The catalyst temperature is less than 100掳C (212掳F).
* The engine coolant temperature is warmer than 10掳C (14掳F).
* The barometric pressure is greater than 70 kPa.
* The engine speed is between 450-1900 RPM.
* The engine is running and a cold start has been detected.
* DTC P050D runs once per cold start.
Conditions for Setting the DTC
This DTC will set if the ECM detects variations in crankshaft rotation speed caused by the lack of adequate fuel delivery during dual-pulse mode.
Action Taken When the DTC Sets
* DTC P050D is a Type B DTC.
* The ECM disables dual pulse mode and energizes the fuel injector as it would for a warm engine.
Conditions for Clearing the DTC
DTC P050D is a Type B DTC.
Diagnostic Aids
* This DTC may be set with a misfire DTC, however the existence of this DTC is a higher priority and indicates the condition to diagnose is
related to fuel and/or injectors, not the ignition/spark system.
* A restricted fuel injector may cause this DTC to set.
* High resistance in the circuits of the injectors could set this DTC without setting an injector DTC. Test the injector circuits of the affected
cylinders for a high resistance if you suspect a condition.
* A drop in system voltage during cold start may set this DTC.
Reference Information
Schematic Reference
Engine Controls Schematics (LLT) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics
(LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
