DTC P050B (LUJ)
Diagnostic Instructions
DTC Descriptor
DTC P050B 00: Cold Start Ignition Timing
Performance |
Circuit/System Description
The throttle actuator control (TAC) motor is controlled by the
engine control module (ECM). The DC motor located in the throttle
body drives the throttle blade. In order to decrease idle speed,
along with spark and fuel delivery changes the ECM commands the
throttle closed reducing air flow into the engine and the idle
speed decreases. In order to increase idle speed, the ECM commands
the throttle plate open allowing more air to pass the throttle
plate. The catalyst must be warmed to efficiently reduce the
emissions. The cold start strategy is to reduce the amount of time
it takes to warm the catalyst. During a cold start, the engine idle
speed is elevated to allow the catalyst to warm quickly.
Conditions for Running the DTC
• |
DTCs P0010 00, P0016 00, P0068
00, P0106 00, P0107 00, P0108 00, P0116 00, P0117 00, P0118 00,
P0119 00, P0121 00, P0123 00, P0171 00, P0172 00, P0201 00, P0202
00, P0203 00, P0204 00, P0222 00, P0261 00, P0262 00, P0264 00,
P0265 00, P0267 00, P0268 00, P0270 00, P0271 00, P0335 00, P0336
00, P0340 00, P0341 00, P0365 00, P0366 00, P0443 00, P0459 00,
P0496 00, P2088 00, P2089 00, P2100 00, P2101 00, P2122 00, P2123
00, P2127 00, P2128 00, P2138 00 are not set. |
• |
The battery voltage is greater
than 10 V. |
• |
The engine speed is at
idle. |
• |
The engine coolant temperature
(ECT) is greater than -9.75°C (14.45°F). |
• |
DTC P050B 00 runs continuously
when the above conditions are met. |
Conditions for Setting the DTC
The actual ignition timing retard value is insufficient for 5 s
or more during 10 s of P050A monitoring duration at cold start.
Action Taken When the DTC Sets
DTC P050B 00 is a Type B DTC.
Conditions for Clearing the DTC
DTC P050B 00 is a Type B 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 Verification
1. |
Engine running, compare the
Desired Idle Speed to the actual engine idle speed parameter. The
actual engine idle speed should not deviate more than 175 RPM from
the Desired Idle Speed. |
2. |
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. |
Circuit/System Testing
1. |
Verify that no DTCs except
P050B 00 are present. |
2. |
Inspect for any condition that
can reduce idle speed by increasing engine load. |
|
• |
Incorrect torque converter
clutch (TCC) operation |
|
• |
Accessories that require
additional torque to operate |
|
• |
Excessive deposits in the
throttle body |
|
• |
Mechanical conditions that
limit engine speed |
3. |
Inspect for the following
conditions: |
|
• |
A faulty positive crankcase
ventilation system |
4. |
Inspect the ignition coil
spark plug boots for the following conditions: |
⇒ |
If you find any of the above conditions, repair as
necessary. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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