Dtc P0116 (Flash Code 23) - Isuzu N 2008 Series Workshop Manual

1A-104 Engine Control System (4JJ1)

DTC P0116 (Flash Code 23)

Circuit Description
The engine coolant temperature (ECT) sensor is
installed to the thermostat housing. The ECT sensor is
a variable resistor and it measures the temperature of
the engine coolant. If the ECM detects that the
difference of engine coolant temperature is smaller
than the calculated range during the predetermined
conditions, this DTC will set. This DTC will only run
once per ignition cycle within the enabling condition.
Condition for Running the DTC
• DTCs P0117, P0118, P0201 - P0204, P0500,
P0502, P0503, P060B, P0697, P1261, P1262,
P2146 and P2149 are not set.
• The battery voltage is between 18 to 32 volts.
• The ignition switch is ON.
• The vehicle runtime is longer than 5 minutes with
the vehicle speed is more than 5 km/h (3 MPH).
• The engine runtime is longer than 5 minutes with
the engine speed is more than 1500 RPM.
• The accumulation fuel injection quantity since
engine start is more than a threshold.
Circuit/ System Testing DTC P0116
Step
Did you perform the Diagnostic System Check -
1 Engine Controls?
1. Test the engine cooling system for the
following conditions. Refer to Cooling System
in Section 1C Engine Cooling.
• Engine coolant level
2
• Engine coolant leakage
2. Repair or replace as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the engine coolant temperature
sensor (ECT) sensor harness connector.
3. Inspect
connections and corrosion at the harness
connector of the ECT sensor (pins 1 and 2 of
E25).
3
4. Disconnect the ECM harness connector.
5. Inspect
connections and corrosion at the harness
connector of the ECM (pins 84 and 109 of
E12).
6. Repair the connection(s) as necessary.
Did you find and correct the condition?
Action
for an intermittent,
for an intermittent,
Condition for Setting the DTC
• The ECM detects that the difference of maximum
and minimum engine coolant temperature is less
than 1 to 10 °C (1.8 to 18°F).
Action Taken When the DTC Sets
• The ECM illuminates the MIL on the second
consecutive driving cycle when the diagnostic runs
and fails. Refer to DTC Type Definitions for Action
Taken When the DTC Sets - Type B.
Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for
Clearing the MIL/ DTC - Type B.
Diagnostic Aids
• After starting the engine, the ECT should rise
steadily to about 80 to 85°C (176 to 185°F) then
stabilize when the thermostat opens.
• Use the Temperature vs. Resistance table to test
the ECT sensor at various temperature levels to
evaluate the possibility of a skewed sensor. A
skewed sensor could result in poor driveability
concerns.
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Value(s)
—
—
for poor
—
for poor
Yes
Go to Diagnostic
System Check -
Go to Step 2 Engine Controls
Go to Step 6 Go to Step 3
Go to Step 6 Go to Step 4
No