Aleromod.com - View Single Post

a.graham52 · 12-09-2011, 07:21 AM

DTC P0128
Circuit Description

An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the powertrain control module (PCM) for engine control and as an enabling criteria for some diagnostics.

The air flow coming into the engine is accumulated and used to determine if the engine has been driven within 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 diagnostics that use ECT as enabling criteria may not run when expected.

This DTC will only run once per ignition cycle within the enabling condition. If the PCM detects the calibrated amount of air flow and engine run time have been met, and the ECT has not met the minimum thermostat regulating temperature, DTC P0128 sets.

Conditions for Running the DTC

• The engine is running.

• DTCs P0112, P0113, P0117, P0118 are not set.

• The ECT is more than −40°C (−40°F).

• The ECT is less than 78°C (172°F).

• The intake air temperature (IAT) is more than −7°C (+19°F).

• The engine has been running for more than 2 minutes, but less than 30 minutes.

• The vehicle speed is more than 24 km/h (15 mph) for more than 1.609 km (1 mile).

• The mass air flow (MAF) average reading is more than 15 g/s.

Conditions for Setting the DTC

The PCM detects the following:

• The calibrated amount of engine run time has been met.

• The calibrated amount of engine air flow has been met.

• The calibrated ECT of 80°C (176°F) has not been met.

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.

Conditions for Clearing the MIL/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.

12-09-2011, 07:21 AM	#4
a.graham52 Premier V.I.P. Member Join Date: Dec 2009 Location: New Hampshire Posts: 1,979	DTC P0128 Circuit Description An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the powertrain control module (PCM) for engine control and as an enabling criteria for some diagnostics. The air flow coming into the engine is accumulated and used to determine if the engine has been driven within 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 diagnostics that use ECT as enabling criteria may not run when expected. This DTC will only run once per ignition cycle within the enabling condition. If the PCM detects the calibrated amount of air flow and engine run time have been met, and the ECT has not met the minimum thermostat regulating temperature, DTC P0128 sets. Conditions for Running the DTC • The engine is running. • DTCs P0112, P0113, P0117, P0118 are not set. • The ECT is more than −40°C (−40°F). • The ECT is less than 78°C (172°F). • The intake air temperature (IAT) is more than −7°C (+19°F). • The engine has been running for more than 2 minutes, but less than 30 minutes. • The vehicle speed is more than 24 km/h (15 mph) for more than 1.609 km (1 mile). • The mass air flow (MAF) average reading is more than 15 g/s. Conditions for Setting the DTC The PCM detects the following: • The calibrated amount of engine run time has been met. • The calibrated amount of engine air flow has been met. • The calibrated ECT of 80°C (176°F) has not been met. 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. Conditions for Clearing the MIL/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. __________________ The dumbass that shows up randomly 10 years after selling the car.