DTC P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
HINT: This DTC relates to the thermostat.
DESCRIPTION This DTC is set when the Engine Coolant Temperature (ECT) does not reach 75C (167F) despite sufficient engine warm-up time
DTC No. |
DTC Detection Condition |
Trouble Area |
P0128 |
Conditions (a), (b) and (c) are met for 5 seconds (2 trip
detection logic):
|
|
MONITOR DESCRIPTION
The ECM estimates the ECT based on the starting temperature, engine loads, and engine speeds. The ECM then compares the estimated temperature with the actual ECT. When the estimated ECT reaches 75C (167F), the ECM checks the actual ECT. If the actual ECT is less than 75C (167F), the ECM interprets this as a malfunction in the thermostat or the engine cooling system and sets the DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
INSPECTION PROCEDURE
HINT: Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction
1 CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0128)
Result
HINT: If any DTCs other than P0128 are output, troubleshoot those DTCs first.
2 CHECK COOLING SYSTEM
3 INSPECT THERMOSTAT
Standard: 80 to 84C (176 to 183F)
HINT: In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.
REPLACE ECM
Antenna Coil Open / Short
DTC B2784 Antenna Coil Open / Short
DESCRIPTION
The transponder key coil is built into the transponder key amplifier and
receives a key code signal from
the transponder chip in the key. This signal is amplified by the amplifier, and
output to the transponder key
ECU.
DTC No.
...
Meter panel light control
The brightness of the meter panel lights can be adjusted.
Pressing the button will adjust the
brightness of the meter panel
lights.
The brightness level of the meters
when the surroundings are bright
(day mode) and dark (night mode)
can be adjusted individually. However,
when in day ...
Data list / active test
1. READ DATA LIST
HINT:
Using the intelligent tester to read the Data List allows
the values or states of switches, sensors, actuators and
other items to be read without removing any parts. This
non-intrusive inspection can be very useful because
intermittent conditions or signals may be disco ...