Nissan Sentra Service Manual: Control Units and Electrical Parts
PRECAUTIONS
- Never reverse polarity of battery terminals.
- Install only parts specified for a vehicle.
- Before replacing the control unit, check the input and output and functions of the component parts.
- Do not apply excessive force when disconnecting a connector.
- Do not apply excessive shock to the control unit by dropping or hitting it.
- Be careful to prevent condensation in the control unit due to rapid temperature changes and do not let water or rain get on it. If water is found in the control unit, dry it fully and then install it in the vehicle.
- Be careful not to let oil to get on the control unit connector.
- Avoid cleaning the control unit with volatile oil.
- Do not disassemble the control unit, and do not remove the upper and lower covers.
- When using a DMM, be careful not to let test probes get close to each other to prevent the power transistor in the control unit from damaging battery voltage because of short circuiting.
- When checking input and output signals of the control unit, use the specified check adapter.
Work Flow
STEP
DESCRIPTION
STEP 1
Get detailed information about the conditions and the
environment when the incident occurred.
The following are key pieces of information requi ...
How to Check Terminal
CONNECTOR AND TERMINAL PIN KIT
Use the connector and terminal pin kits listed below when replacing
connectors or terminals.
The connector and terminal pin kits contain some of the most common ...
Other materials:
DTC/Circuit diagnosis
U0073 COMMUNICATION BUS A OFF
DTC Logic
DTC DETECTION LOGIC
DTC
CONSULT screen terms
(Trouble diagnosis content)
DTC detection condition
Possible causes
U0073
COMM BUS A OFF
(Control Module Communication
Bus A Off)
TCM communication blockage lasts for 2 sec ...
Symptom diagnosis
Squeak and rattle trouble diagnoses
Work Flow
CUSTOMER INTERVIEW
Interview the customer if possible, to determine the conditions that exist
when the noise occurs. Use the Diagnostic
Worksheet during the interview to document the facts and conditions when the
noise occurs and any
custome ...
Cooling fan control
SYSTEM DIAGRAM
SYSTEM DESCRIPTION
ECM controls cooling fan speed corresponding to vehicle speed, engine coolant
temperature, refrigerant pressure,
air conditioner ON signal. Then control system has 3-step control
[HIGH/LOW/OFF].
Cooling Fan Operation
Cooling Fan Relay Operation
Whe ...
