DTC P1258
| DTC P1258 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptors |
DTC P1258
Engine Coolant Overtemperature - Protection Mode Active
| Circuit/System Description |
The engine control module (ECM) uses the engine coolant temperature sensor to monitor the engine for an over-temperature condition. This condition occurs when the coolant temperature is above a calibrated value. The ECM will alternately disable 2 groups of cylinders by turning OFF the fuel injectors. By switching between the 2 groups of cylinders, the ECM is able to reduce the temperature of the coolant.
| Conditions for Running the DTC |
LF1, LFW, LFX
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The engine is operating for greater than 30 seconds.
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DTC P1258 runs continuously once the conditions above have been met.
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LAU
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DTCs P0116, P0117, P0118, P0119 are not set.
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The engine speed is higher than 80 RPM
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The engine is operating for greater than 30 seconds.
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DTC P1258 runs continuously once the conditions above have been met.
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| Conditions for Setting the DTC |
LF1, LFW, LFX
- The ECM detects that engine coolant temperature is warmer than 129°C (264°F) for greater than 2 seconds.- if protection mode is activated and ECT detects that DTC(s) has/have been set then protection mode will remain activated for the new driving cycle until ETC detects that the DTC operation is running fault-free
LAU
The ECM detects that engine coolant temperature is warmer than 133°C (271°F) for greater than 1 second.| Action Taken When the DTC Sets |
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DTC P1258 is a Type A DTC.
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The engine will operate in the Overheated Engine Protection Operating Mode.
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The IP will illuminate the coolant temperature indicator lamp and the driver information centre (DIC), if equipped, may display a message.
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| Conditions for Clearing the MIL/DTC |
DTC P1258 is a Type A DTC.
| Reference Information |
Schematic Reference
Engine Controls Schematics (3.0L (LF1)) Engine Controls Schematics (2.8L (LAU))
Connector End View Reference
Component Connector End Views
Description and Operation
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Cooling Fan Description and Operation (LF1)
Cooling Fan Description and Operation (LAU)
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Instrument Cluster Description and Operation
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Indicator/Warning Message Description and Operation
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Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Engine control module, scan tool information (LF1, LFW)
Engine control module, scan tool information (LAU)
| Circuit/System Verification |
| Note | ||
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If DTC P0480, P0481, P0691, P0692, P0693, or P0694 is set, diagnose that DTC first. |
| 1. |
Observe the engine coolant level. The engine coolant level should be within the operating range. See
Cooling System Draining and Filling (GE 47716) |
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| 2. |
Ensure that the vehicle has the correct engine coolant with correct concentration and is not old, contaminated, or contains additives. See
Cooling System Draining and Filling (GE 47716) |
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| 3. |
Inspect the cooling system for the following:
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Leaks
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Kinked or pinched hoses, especially at the radiator
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Loose, missing, or damaged radiator air seals or deflectors
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Air flow obstructions or bent fins at the radiator or the A/C condenser-Refer to
Symptoms - Engine Cooling
.
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| 4. |
Command the cooling fans ON and OFF, low and high speed. The engine cooling fans should turn ON and OFF with each command. |
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| 5. |
If the cooling fans do not function as indicated, refer to
Cooling Fan Inoperative (LAU)
;
Cooling Fan Inoperative (LF1, LFW, LFX)
.
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| Circuit/System Testing |
| 1. |
Test the thermostat for correct operation. Refer to
Thermostat Diagnosis
.
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| 2. |
Test the engine cooling system for overheating. Refer to
Engine Overheating
.
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| 3. |
Inspect the water pump and coolant flow for correct operation. Refer to
Water Pump Cleaning and Inspection
.
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| 4. |
Inspect the engine mechanical for worn, leaking, cracked cylinder heads or engine block. Refer to
Coolant in Engine Oil
.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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