Diagnosis Procedure

WARNING: This page is about a different car, the 2018 Nissan Titan XD. However, it is still accessible from the selected car via links, so may be relevant.

CHECK DTC PRIORITY
1. Turn ignition switch ON.
2. Connect CONSULT and check for "ENGINE" diagnostic trouble codes.
3. Check for DTC P2559 - 00 being current on the CONSULT screen.
Is the inspection result normal?

YES

GO TO 2 .

NO

Refer to Intermittent Incident .
INSPECT COOLANT LEVEL SENSOR AND CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect coolant level sensor connector E91.
3. Inspect the harness and sensor connector pins for the following:
  - Loose connector
  - Corroded pins
  - Bent or broken pins
  - Pushed back or expanded pins
  - Moisture in or on the connector
  - Missing or damaged connector seals
  - Dirt or debris on or in the connector pins
  - Connector shell broken
  - Wire insulation damage
  - Damaged connector locking tab
Is the inspection result normal?

YES

GO TO 3 .

NO

Repair or replace error-detected parts.
CHECK CIRCUIT RESPONSE
1. Coolant level sensor connector E91 remains disconnected.
2. Connect a jumper wire between terminals 1 and 2 of the coolant level sensor connector E91.
3. Turn ignition switch ON.
4. Check for DTC P2559 - 00 being current and P2558 - 00 being past on the CONSULT screen after 30 seconds.
Is the inspection result normal?

YES

GO TO 4 .

NO

GO TO 5 .
CHECK DTCS AND VERIFY SENSOR CONDITION
1. Turn ignition switch OFF.
2. Connect coolant level sensor connector E91.
3. Turn ignition switch ON.
4. Check for DTC P2559 - 00 being current on the CONSULT screen after 30 seconds.
Is the inspection result normal?

YES

Replace the engine coolant level sensor. Refer to Removal and Installation .

NO

The removal and installation of the connector corrected the fault.
INSPECT ECM AND CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect ECM connector E93.
3. Inspect the harness and module connector pins for the following:
  - Loose connector
  - Corroded pins
  - Bent or broken pins
  - Pushed back or expanded pins
  - Moisture in or on the connector
  - Missing or damaged connector seals
  - Dirt or debris on or in the connector pins
  - Connector shell broken
  - Wire insulation damage
  - Damaged connector locking tab.
Is the inspection result normal?

YES

GO TO 6 .

NO

Repair or replace error-detected parts.

CHECK FOR AN OPEN RETURN CIRCUIT

Turn ignition switch OFF.
Disconnect jumper wire between terminals 1 and 2 of the coolant level sensor connector E91.

Check resistance between ECM connector E93 and coolant level sensor connector E91.

ECM		Coolant level sensor		Resistance
Connector	Terminal	Connector	Terminal	Resistance
E93	41	E91	1	< 10 Ω

Is the inspection result normal?

YES

GO TO 7 .

An open return circuit has been detected in the engine harness. Repair or replace the engine harness.

CHECK FOR AN OPEN SIGNAL CIRCUIT

Disconnect ECM connector E93 and coolant level sensor connector E91.

Check resistance between ECM connector E93 and coolant level sensor connector E91.

ECM		Coolant level sensor		Resistance
Connector	Terminal	Connector	Terminal	Resistance
E93	75	E91	2	< 10 Ω

Is the inspection result normal?

YES

GO TO 8 .

An open signal circuit has been detected in the engine harness. Repair or replace the engine harness.

CHECK FOR A SHORT CIRCUIT

Check resistance between the terminals of ECM connector E93.

ECM		ECM		Resistance
Connector	Terminal	Connector	Terminal	Resistance
E93	75	E93	All	> 100k Ω

Is the inspection result normal?

YES

GO TO 9 .

A short circuit has been detected on the signal circuit in the engine harness. Repair or replace the engine harness.

CHECK DTC PRIORITY
1. Turn ignition switch ON.
2. Connect all components.
3. Connect CONSULT and check for "ENGINE" diagnostic trouble codes.
4. Check for DTC P2559 - 00 being past on the CONSULT screen after 30 seconds.
Is the inspection result normal?

YES

The removal and installation of the connector corrected the fault.

NO

Replace ECM. Refer to Removal and Installation .