Aston Martin diagnostic trouble code
P0118: Engine Coolant Temperature Circuit High Input
Use this reference to understand the recorded condition, confirm the available V8 Vantage or DB9 manual coverage, and follow the documented diagnostic checks before replacing parts.
- Code family
- Powertrain
- Vehicle system
- Cooling and temperature
- Manual coverage
- V8 Vantage, DB9
- Warning-lamp status
- V8 Vantage: MIL; DB9: MIL
What Aston Martin code P0118 means
Engine Coolant Temperature Circuit High Input
DB9 preliminary diagnostic manual · section 2-26
Manufacturer fault-analysis procedure
Manual fault definition
P0117 - The ECT signal went below 0.2 volts during continuous testing. (I.e. Excessively high temperature)
P0118 - The ECT signal went above 4.60 volts
during continuous testing. (i.e. Excessively low
temperature)
P0119 - The ECT signal was intermittent or erratic.
P0118 - The ECT signal went above 4.60 volts
during continuous testing. (i.e. Excessively low
temperature)
P0119 - The ECT signal was intermittent or erratic.
Cautions and notes
CAUTION: These codes should be generated only
in the Primary PCM. Check that you are working
on the correct half of the engine.
in the Primary PCM. Check that you are working
on the correct half of the engine.
Test sequence and decision path
1. Connect the WDS or scan tool and confirm that
P0117, P0118 or P0119 is present.
2. Run the engine and use the datalogger to read the
voltage of the engine coolant temperature signal.
The voltage should be in the range 0.25 - 3.50
volts (see the table of ECT Sensor Values).
For low readings (P0117) go to step 3
For high readings (P0118) go to step 4
3. P0117 - For low voltage readings, suspect a short
circuit of the signal (Primary PCM pin C0636-33)
to chassis ground or to signal return pin C0636-
41. Key off, check for short circuit between the lines
from PCM pin C0636-33 to the ECT sensor body
and from pin C0636-33 to signal return pin
C0636-41 and to power grounds PCM pins
C0635-10, 47, 48 and 49.
4. P0118 - For high voltage readings (above 3.50
volts) suspect an open circuit in the sensor wiring
or internally within the sensor.
Key off, disconnect the ECT sensor, measure the
voltage across the ECT sensor connector. Approximately 5.0 volts should be present. If not, there is
an open circuit in the line from PCM pin C0636-
33 or in the return line to PCM pin C063-41.
If approximately 5.0 volts is present, check the
resistance of the ECT sensor. Consult the table
below, the resistance should be within 15% of the
values in the table. If the resistance is very high or
infinite, change the IAT sensor.
If the results of the above checks are satisfactory
and a P0118 code continues to be logged, consult Aston Martin Technical Support.
5. P0119 - For intermittent/erratic signal levels,
monitor the ECT signal whilst shaking/wiggling
the engine harness between the ECT sensor and
the PCM.
If any inconsistency is identified, service the
affected part of the harness as necessary. Clear
the P0119 code and run a KOER test to ensure
that the problem is resolved.
6. Clear the P0117/P0118 code, run the drive cycle
to ensure that the problem is resolved.
Table of ECT Sensor Values
Temperature Voltage Resistance
°F °C Volts K Ohms
248 120 0.27 1.18
230 110 0.35 1.55
212 100 0.46 2.07
194 90 0.60 2.80
176 80 0.78 3.84
158 70 1.02 5.37
140 60 1.33 7.70
122 50 1.70 10.97
104 40 2.13 16.15
86 30 2.60 24.27
68 20 3.07 37.30
50 10 3.51 58.75
Open the corresponding manual page for wiring diagrams and figures
P0117, P0118 or P0119 is present.
2. Run the engine and use the datalogger to read the
voltage of the engine coolant temperature signal.
The voltage should be in the range 0.25 - 3.50
volts (see the table of ECT Sensor Values).
For low readings (P0117) go to step 3
For high readings (P0118) go to step 4
3. P0117 - For low voltage readings, suspect a short
circuit of the signal (Primary PCM pin C0636-33)
to chassis ground or to signal return pin C0636-
41. Key off, check for short circuit between the lines
from PCM pin C0636-33 to the ECT sensor body
and from pin C0636-33 to signal return pin
C0636-41 and to power grounds PCM pins
C0635-10, 47, 48 and 49.
4. P0118 - For high voltage readings (above 3.50
volts) suspect an open circuit in the sensor wiring
or internally within the sensor.
Key off, disconnect the ECT sensor, measure the
voltage across the ECT sensor connector. Approximately 5.0 volts should be present. If not, there is
an open circuit in the line from PCM pin C0636-
33 or in the return line to PCM pin C063-41.
If approximately 5.0 volts is present, check the
resistance of the ECT sensor. Consult the table
below, the resistance should be within 15% of the
values in the table. If the resistance is very high or
infinite, change the IAT sensor.
If the results of the above checks are satisfactory
and a P0118 code continues to be logged, consult Aston Martin Technical Support.
5. P0119 - For intermittent/erratic signal levels,
monitor the ECT signal whilst shaking/wiggling
the engine harness between the ECT sensor and
the PCM.
If any inconsistency is identified, service the
affected part of the harness as necessary. Clear
the P0119 code and run a KOER test to ensure
that the problem is resolved.
6. Clear the P0117/P0118 code, run the drive cycle
to ensure that the problem is resolved.
Table of ECT Sensor Values
Temperature Voltage Resistance
°F °C Volts K Ohms
248 120 0.27 1.18
230 110 0.35 1.55
212 100 0.46 2.07
194 90 0.60 2.80
176 80 0.78 3.84
158 70 1.02 5.37
140 60 1.33 7.70
122 50 1.70 10.97
104 40 2.13 16.15
86 30 2.60 24.27
68 20 3.07 37.30
50 10 3.51 58.75