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Nissan Altima L32. Manual - part 613

PRECAUTIONS

EC-1573

< PRECAUTION >

[VQ35DE]

On Board Diagnostic (OBD) System of Engine and CVT

INFOID:0000000004362403

The ECM has an on board diagnostic system. It will illuminate the malfunction indicator lamp (MIL) to warn the

driver of a malfunction causing emission deterioration.

CAUTION:

• Always to 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 MIL to illuminate.

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

cause the MIL to illuminate due to the open circuit. (Always 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-58, "Description"

(coupe) or

PG-129, "Description"

(sedan).

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

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

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

may cause the MIL to illuminate due to the malfunction of the EVAP system or fuel injection system,

etc.

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

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

General Precautions

INFOID:0000000004362404

• 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.

- ECM (2)

- Loosen (A)

SEF289H

PBIB2947E

EC-1574

< PRECAUTION >

[VQ35DE]

PRECAUTIONS

• 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 that the ECM functions properly.

Refer to

EC-1510, "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 leakage in the air intake system can cause seri-

ous 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.

PBIB0090E

MEF040D

SEF217U

PRECAUTIONS

EC-1575

< PRECAUTION >

[VQ35DE]

• 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.

• 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.

SEF348N

SEC893C

SEF709Y

EC-1576

< PRECAUTION >

[VQ35DE]

PRECAUTIONS

• 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.

SEF708Y

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