Scribd
Upload
3K views1 page

MID 128, PID 110 Coolant Temperature: MID 128: Engine Control Unit Fault Code

The document summarizes a malfunction in the electrical system related to coolant temperature sensor issues. It provides details on fault codes MID 128, PID 110, including fault code explanations for FMI 0 and 4/5. Symptoms and circuit descriptions are described for each fault code. The summary includes fault indications, symptoms, and that the coolant temperature sensor uses a thermistor that changes resistance based on coolant temperature.

Uploaded by

user1
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
3K views1 page

MID 128, PID 110 Coolant Temperature: MID 128: Engine Control Unit Fault Code

The document summarizes a malfunction in the electrical system related to coolant temperature sensor issues. It provides details on fault codes MID 128, PID 110, including fault code explanations for FMI 0 and 4/5. Symptoms and circuit descriptions are described for each fault code. The summary includes fault indications, symptoms, and that the coolant temperature sensor uses a thermistor that changes resistance based on coolant temperature.

Uploaded by

user1
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 1

Group 30: Electrical system Malfunctions, MID 128

MID 128, PID 110


Coolant temperature

MID 128: Engine control unit


Fault code
FMI 0: The sensor value is valid but exceeds the nor-
mal working range.
FMI 4: The voltage is less than the normal value or is
short circuited to battery negative.
FMI 5: The current is less than the normal value or is
open circuited.

FMI Fault code explanation


0 Excessive coolant temperature
4.5 Faulty sensor / Faulty sensor circuit

Fault indication
FMI 0: The warning symbol in the alarm panel
flashes red. The coolant temperature sym-
bol in the alarm panel flashes red. Audible
warning.
FMI 4, 5: Orange lamp flashes in the alarm panel.
The coolant temperature gauge shows 0.
The display shows – – –.

Symptom
FMI 0: Engine power is cut.
FMI 4, 5: None

Circuit description
The coolant temperature sensor consists of a ther-
mistor which forms a closed circuit with the engine
control unit. The property of a thermistor is that its re-
sistance changes non-linearly with temperature in the
Connector B Coolant temperature sensor medium it measures. The engine control unit, pin 27,
supplies the sensor, pin 2 with a reference voltage of
+5 Volt. The sensor, pin 1, is connected to battery
negative via the engine control unit, pin 18.
When the coolant is cold, the thermistor resistance is
high and the engine control unit senses a voltage
close to the reference level. When the coolant heats
up, the resistance in the thermistor falls and the volt-
age drop across it falls.
Please refer to the table, ”resistance/temperature”.

61

You might also like