Nissan Teana J32. Manual - part 467

EC-406

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PRECAUTIONS

CAUTION:

• Always turn the ignition switch OFF and disconnect the negative battery cable before any repair or

inspection work. The open/short circuit of related switches, sensors, solenoid valves, etc. will cause
the MI to illuminate.

• Always connect and lock the connectors securely after work. A loose (unlocked) connector will

cause the MI to illuminate due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)

• Certain systems and components, especially those related to OBD, may use a new style slide-lock-

ing type harness connector. For description and how to disconnect, refer to 

PG-96, "Description"

.

• Always to route and secure the harnesses properly after work. The interference of the harness with a

bracket, etc. may cause the MI to illuminate due to the short circuit.

• Always connect rubber tubes properly after work. A misconnected or disconnected rubber tube may

cause the MI to illuminate due to the malfunction of the EVAP system or fuel injection system, etc.

• Always erase the unnecessary malfunction information (repairs completed) from the ECM and TCM

(Transmission control module) before returning the vehicle to the customer.

General Precautions

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• Always use a 12 volt battery as power source.
• Never attempt to disconnect battery cables while engine is

running.

• Before connecting or disconnecting the ECM harness con-

nector, turn ignition switch OFF and disconnect negative bat-
tery cable. Failure to do so may damage the ECM because
battery voltage is applied to ECM even if ignition switch is
turned OFF.

• Before removing parts, turn ignition switch OFF and then dis-

connect battery ground cable.

• Never disassemble ECM.
• If a battery cable is disconnected, the memory will return to the ECM value.

The ECM will now start to self-control at its initial value. Thus, engine operation can vary slightly in
this case. However, this is not an indication of a malfunction. Never replace parts because of a slight
variation.

• If the battery is disconnected, the following emission-related diagnostic information will be lost

within 24 hours.

- Diagnostic trouble codes
- 1st trip diagnostic trouble codes
- Freeze frame data
- 1st trip freeze frame data
- System readiness test (SRT) codes
- Test values
• When connecting ECM harness connector, fasten (B) it

securely with a lever (1) as far as it will go as shown in the fig-
ure.

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:  ECM

A

: Loosen

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PRECAUTIONS

EC-407

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• When connecting or disconnecting pin connectors into or

from ECM, never damage pin terminals (bends or break).
Check that there are not any bends or breaks on ECM pin ter-
minal, when connecting pin connectors.

• Securely connect ECM harness connectors.

A poor connection can cause an extremely high (surge) volt-
age to develop in coil and condenser, thus resulting in dam-
age to ICs.

• Keep engine control system harness at least 10 cm (4 in) away

from adjacent harness, to prevent engine control system mal-
functions due to receiving external noise, degraded operation
of ICs, etc.

• Keep engine control system parts and harness dry.
• Before replacing ECM, perform ECM Terminals and Reference

Value inspection and check ECM functions properly. Refer to

EC-357, "Reference Value"

.

• Handle mass air flow sensor carefully to avoid damage.
• Never clean mass air flow sensor with any type of detergent.
• Never disassemble electric throttle control actuator.
• Even a slight leak in the air intake system can cause serious

incidents.

• Never shock or jar the camshaft position sensor (PHASE),

crankshaft position sensor (POS).

• After performing each TROUBLE DIAGNOSIS, perform DTC

Confirmation Procedure or Component Function Check.
The DTC should not be displayed in the DTC Confirmation
Procedure if the repair is completed. The Component Func-
tion Check should be a good result if the repair is completed.

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EC-408

< PRECAUTION >

[VQ25DE, VQ35DE]

PRECAUTIONS

• When measuring ECM signals with a circuit tester, never allow

the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.

• Never use ECM ground terminals when measuring input/out-

put voltage. Doing so may result in damage to the ECM's tran-
sistor. Use a ground other than ECM terminals, such as the
ground.

• B1 indicates bank 1, B2 indicates bank 2 as shown in the fig-

ure.

• Never operate fuel pump when there is no fuel in lines.
• Tighten fuel hose clamps to the specified torque.

• Never depress accelerator pedal when starting.
• Immediately after starting, never rev up engine unnecessarily.
• Never rev up engine just prior to shutdown.

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PRECAUTIONS

EC-409

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• When installing C.B. ham radio or a mobile phone, be sure to

observe the following as it may adversely affect electronic
control systems depending on installation location.

- Keep the antenna as far as possible from the electronic con-

trol units.

- Keep the antenna feeder line more than 20 cm (8 in) away

from the harness of electronic controls.
Never let them run parallel for a long distance.

- Adjust the antenna and feeder line so that the standing-wave

ratio can be kept smaller.

- Be sure to ground the radio to vehicle body.

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