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what are these codes?.thanks brad
 

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Document ID# 1625680
2006 GMC Truck GMC K Sierra - 4WD
DTC P0128

<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss1-1625680">Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Strategy Based Diagnosis
Diagnostic Procedure Instructions
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss2-1625680">DTC Descriptor

DTC P0128: Engine Coolant Temperature (ECT) Below Thermostat Temperature

<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss3-1625680">Diagnostic Fault Information

Circuit
Short to Ground
Open/High Resistance
Short to Voltage
Signal Performance
ECT Sensor Signal
P0117
P0118
P0118
P0116, P0128
Low Reference
P0118
P0118
P0128
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss4-1625680">Typical Scan Tool Data

<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#tab5-1625680">ECT Sensor Temperature

Circuit
Normal Range
Short to Ground
Open
Short to Voltage
Operating Conditions: Key ON, engine OFF
ECT Sensor Signal
¹Varies
150°C (302°F)
-40°C (-40°F)
-40°C (-40°F)
Low Reference
--
--
-40°C (-40°F)
-40°C (-40°F)
¹ Varies -39 to +149°C (-38 to +300°F)
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss6-1625680">Circuit/System Description

The engine control module (ECM) uses this diagnostic to determine if the engine coolant temperature (ECT) has reached the minimum calibrated thermostat regulating temperature. The ECM supplies 5 volts to the ECT signal circuit , and a ground for the ECT low reference circuit. The ECM monitors the temperature of the coolant by using the input received from the ECT sensor. The ECM calculates the amount of fuel burned since start-up to determine if the vehicle has been driven within the conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally, or does not reach the regulating temperature of the thermostat, the engine is considered not warm enough for stable, low emission operation.
The purpose of both these rationality diagnostics is to use the ECT sensor to determine if the engine coolant will heat up at the correct rate, and also meet the calibrated target temperatures under various operating conditions.
The ECM uses the start-up ECT and the start-up intake air temperature (IAT) to begin the diagnostic calculation.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss7-1625680">Conditions for Running the DTC

• DTC P0112, P0113, P0116, P0117, P0118 are not set.
• The engine is running.
• The IAT 1 is greater than -7°C (19°F), but less than 100°C (212°F).
• The start-up engine coolant temperature is less than 65°C (149°F).
• DTC P0128 will only run once per ignition cycle until a Pass, Fail or Disable condition exists.​
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss8-1625680">Conditions for Setting the DTC

The engine did not meet the ECT target temperature of 45°C (113°F) or 72°C (162°F) during expected calibrated warm-up times and start-up temperatures.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss9-1625680">Action Taken When the DTC Sets

• The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.​
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss10-1625680">Conditions for Clearing the DTC

• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
• Clear the MIL and the DTC with a scan tool.​
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss11-1625680">Diagnostic Aids

DTC P0128 is designed to detect for a stuck open thermostat.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1625680&psdid=1233&evc=sm#ss12-1625680">Reference Information

Schematic Reference

Engine Controls Schematics
 

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Pd YOU SURE ????
 

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Discussion Starter #4
yes that is what the powerpup said.
 

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Discussion Starter #5
anybody else know about the 26?thanks
 
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