Tech Tip: Toyota Charging Improvement at Idle – UnderhoodService

Tech Tip: Toyota Charging Improvement at Idle

Some customers with a 1998-2003 Sienna may complain of a low battery or no-start condition after running the engine at idle or low RPM for extended

Some customers with a 1998-2003 Sienna may complain of a low battery or no-start condition after running the engine at idle or low RPM for extended ­periods of time with several accessories on during high-temperature conditions.

A new alternator has been developed to improve charging performance at idle.

Note: This new alternator will not prevent dead batteries or no-start conditions on vehicles that are stored for long periods of time or on vehicles that are driven very infrequently.

Repair Procedure:

Note: Confirm that the vehicle does not have an ­unusual parasitic load on the battery with key off and doors locked. Parasitic load should be less than 40 mA.figure 1

1. Disconnect the negative terminal from the vehicle battery.figure 2

2. Disconnect the alternator wire and connector. See Fig. 1.

3. Remove the drive belt and original alternator. See Fig. 2.figure 3

a. Pull up the retainer in the waterproof connector to disengage the secondary lock. See Fig. 3.

b. Release the locking lug from the terminal and pull the terminal out from the backside of the connector. See Fig. 4.figure 4

c. Remove the connector cover from the vehicle wire harness.

4. Install the new connector onto the alternator harness.

a. Remove the locking ring from the face of the new connector.figure 5

b. Install the terminals into the back of the connector as shown in Fig. 5.

c. Install the black rubber plug included with the alternator kit (P/N 04003-22145) into the location shown in Fig. 5. This step is critical.

Caution: Do not return this vehicle to the customer ­unless the unused terminal location is sealed off from possible water intrusion.

5. Install the new alternator.figure 6

a. Install the alternator, adjusting the lock bolt, plate washer and pivot bolt.

b. Install the wiring harness clamp bracket with the bolt contained in the kit. See Fig. 6.

c. Connect the alternator wire and install the nut.

d. Connect the alternator connector.

e. Connect the wire harness to the clamp.

6. Install the drive belt.Figure 7

a. Install the drive belt and adjust the belt tension.

Drive Belt Tension: 175 +/- 5 lbf.

b. Tighten the adjusting lock bolt and the pivot bolt. See Fig. 7.

Courtesy of IDENTIFIX.

For more information, log onto www.identifix.com.

You May Also Like

Alternator Testing For No Charge Conditions

Many alternator problems turn out to be nothing more than a bad connection at the alternator or a bad wiring harness.

If only battery voltage is present at the battery on a running engine, does this mean the alternator is “bad?” No, it does not. It only means that the alternator is not charging, but does not reveal why. Therefore, it does not point to a faulty alternator. All too often, the alternator is condemned by technicians due to this test alone. The cause could instead be a module that distributes the power to the vehicle and regulates the alternator.

ECM Damage

Engineers have devised two strategies that can be called the “immune system” for the electrical system.

Voltage Drop Testing

The measurement of voltage is like the speed of the traffic.

Spark Plug Fouling

Understanding why spark plugs get dirty.

Understanding Stop/Start Charging and Starting Systems

The problem may not have been caused by a complicated reason, something simple may have caused the system not to work.

Other Posts

Caring For AGM And Flooded Car Batteries

Faulty battery cables, if loose, corroded, or damaged, can lead to power drainage.

Power Window Regulator and Motor Service

Power windows are great as long as they roll up and down when commanded to do so.

Battery Management Means Knowing How It Ages

The battery may be fully charged, but you also need to measure how low the voltages go while the engine is cranking.

Understanding Coolants

All-season coolant used inorganic acid technology and worked great for almost 30 years.