General Information: Diagnosis Nissan Maxima A34

Waterproof Connector Inspection

If water enters the connector, it can short interior circuits. This may lead to intermittent problems. Check the following items to maintain the original waterproof characteristics.

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1. Most waterproof connectors are provided with a rubber seal between the male and female connectors. If the seal is missing, the waterproof performance may not meet specifications.
2. The rubber seal may come off when connectors are disconnected. Whenever connectors are reconnected, make sure the rubber seal is properly installed on either side of male or female connector.

WIRE SEAL INSPECTION

The wire seal must be installed on the wire insertion area of a waterproof connector. Be sure that the seal is installed properly.

Terminal Lock Inspection

Check for unlocked terminals by pulling wire at the end of connector. An unlocked terminal may create intermittent signals in the circuit.

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Testing for "Opens" in the Circuit

Before you begin to diagnose and test the system, you should rough sketch a schematic of the system. This will help you to logically walk through the diagnosis process. Drawing the sketch will also reinforce your working knowledge of the system.

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Testing for "Shorts" in the Circuit

To simplify the discussion of shorts in the system, please refer to the following schematic.

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Ground Inspection

Ground connections are very important to the proper operation of electrical and electronic circuits. Ground connections are often exposed to moisture, dirt and other corrosive elements. The corrosion (rust) can become an unwanted resistance. This unwanted resistance can change the way a circuit works.

Electronically controlled circuits are very sensitive to proper grounding. A loose or corroded ground can drastically affect an electronically controlled circuit. A poor or corroded ground can easily affect the circuit. Even when the ground connection looks clean, there can be a thin film of rust on the surface.

When inspecting a ground connection follow these rules

1. Remove the ground bolt or screw.
2. Inspect all mating surfaces for tarnish, dirt, rust, etc.
3. Clean as required to assure good contact.
4. Reinstall bolt or screw securely.
5. Inspect for "add-on" accessories which may be interfering with the ground circuit.
6. If several wires are crimped into one ground eyelet terminal, check for proper crimps. Make sure all of the wires are clean, securely fastened and providing a good ground path. If multiple wires are cased in one eyelet make sure no ground wires have excess wire insulation.

For detailed ground distribution information, refer to GROUND DISTRIBUTION .

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Control Unit Circuit Test

System Description: When the switch is ON, the control unit lights up the lamp.

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1. Never reverse polarity of battery terminals.
2. Install only parts specified for a vehicle.
3. Before replacing the control unit, check the input and output and functions of the component parts.
4. Do not apply excessive force when disconnecting a connector.
5. If a connector is installed by tightening bolts, loosen bolt mounting it, then take it out by hand.
6. Before installing a connector, make sure the terminal is not bent or damaged, and then correctly connect it. When installing a connector by tightening bolts, fix it by tightening the mounting bolt until the painted projection of the connector becomes even with the surface.
7. For removal of the lever type connector, pull the lever up to the direction pointed to by the arrow A in the figure, and then remove the connector.
8. For installation of the lever type connector, pull down the lever to the direction pointed by the arrow B in the figure, and then push the connector until a clicking noise is heard.
9. Do not apply excessive shock to the control unit by dropping or hitting it.
10. 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.
11. Be careful not to let oil to get on the control unit connector.
12. Avoid cleaning the control unit with volatile oil.
13. Do not disassemble the control unit, and do not remove the upper and lower covers.
14. 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.
15. When checking input and output signals of the control unit, use the specified check adapter.

INSPECTION PROCEDURE

If the CONSULT-II cannot diagnose the system properly, check the following items.

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Note. The DDL1 and DDL2 circuits from DLC pins 12, 13, 14 and 15 may be connected to more than one system. A short in a DDL circuit connected to a control unit in one system may affect CONSULT-II access to other systems.