DTC P050D (LUJ)
Diagnostic Instructions
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.
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.
Conditions for Running the DTC
| • |
DTCs P0101, P0102, P0103,
P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121,
P0122, P0123, P0128, P0171, P0172, P0191, P0192, P0193, P0201,
P0202, P0203, P0204, P0205, P0206, P0220, P0223, P0231, P0232,
P0315, P0335, P0336, P0340, P0341, P0345, P0346, P1682 are not
set. |
| • |
The engine is running and a
cold start has been detected. |
| • |
DTC P050D runs once per cold
start. |
Conditions for Setting the DTC
DTC P050D runs once per cold start.
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
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Note: Circuit/system
Testing requires cold start. Do not start vehicle prior to
connecting scan tool and preparing to evaluate the condition during
engine crank.
| 1. |
Ignition ON, engine OFF, set
the scan tool to view misfire counters. |
| 2. |
Start the engine and observe
misfire counters during first 200 engine cycles. The Misfire
Current Counters should not be incrementing. |
| ⇒ |
If the misfire counters are incrementing on one or
more cylinders, verify that the following conditions do not
exist: |
| 3. |
If all conditions test normal,
replace fuel injectors as indicated by high misfire counts.
|
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Fuel Injector Replacement
Repair Verification
Note: Repair Verification
requires cold start.
| 1. |
Ignition ON, engine OFF, clear
the DTCs with a scan tool. |
| 3. |
Verify the DTC does not
reset. |
|
