Mazda MX-5 Miata / Grand Touring. Manual - part 41

Fig. 6: Connecting Battery Charger To Battery 
Courtesy of MAZDA MOTORS CORP. 

3. After the battery is recharged, verify that the voltage is within the specification and remains at the same 

value for 1 h or more after the recharging was completed. 



If not within the specification, replace the battery.  

Standard voltage  

12.4 V or more  

GENERATOR REMOVAL/INSTALLATION [LF] 

WARNING:



Remove and install all parts when the engine is cold, otherwise they 
can cause severe burns or serious injury.  



When the battery cables are connected, touching the vehicle body 
with generator terminal B will generate sparks. This can cause 
personal injury, fire, and damage to the electrical components. 
Always disconnect the battery negative cable before performing the 
following operation.  

CAUTION:



The generator can be damaged by the heat from the exhaust 

 

2008 Mazda MX-5 Miata Grand Touring 

2008 ELECTRICAL Charging System - MX-5 Miata

  

1. Remove the battery and battery tray. (See BATTERY REMOVAL/INSTALLATION [LF] .)  

2. Remove the drive belt. (See DRIVE BELT REPLACEMENT [LF] .)  

3. Remove in the order indicated in the table.  

4. Install in the reverse order of removal. 

Fig. 7: Identifying Removal Order Of Generator (With Torque Specifications) 
Courtesy of MAZDA MOTORS CORP. 

GENERATOR INSTALLATION NOTE 

1. Tighten bolt A temporarily.  

2. Tighten bolt B, C to the specified tightening torque.  

3. Tighten bolt A to the specified tightening torque.  

GENERATOR INSPECTION [LF] 

manifold. Make sure the generator duct is installed securely.  

 

2008 Mazda MX-5 Miata Grand Touring 

2008 ELECTRICAL Charging System - MX-5 Miata

  

GENERATOR WARNING LIGHT 

1. Verify that the battery is fully charged.  

2. Verify that the drive belt deflection/tension is correct. (See DRIVE BELT INSPECTION [LF] .)  

3. With the ignition switch turned to the ON position, verify that the generator warning light illuminates. 



If it does not illuminate, inspect the generator warning light and the wiring harness. 



If the generator warning light and the wiring harness are normal, inspect the PCM.  

4. Verify that the generator warning light goes out after the engine is started. 



If it does not go out, inspect if any one of the following DTCs in the on-board diagnostic system 
are displayed: P0112, P0113, P2502, P2503, P2504. (See DTC TABLE [LF] .)  

GENERATOR 

Voltage 

1. Verify that the battery is fully charged.  

2. Verify that the drive belt deflection/tension is correct. (See DRIVE BELT INSPECTION [LF] .)  

3. Turn off all electrical loads.  

4. Start the engine.  

5. Verify that the generator rotates smoothly without any noise while the engine is running. 



If there is any noise, find the cause and repair or replace the generator.  

6. Measure the voltage at each terminal using a tester. 

Generator standard voltage [IG-ON]  

Terminal B: B+  

Terminal P: Approx. 1 V or less  

Terminal D: Approx. 0 V  

Generator standard voltage [Idle, 20°C {68°F}]  

Terminal B: 13-15 V  

Terminal P: Approx. 3-8 V  

Terminal D: Turn the electrical loads (headlights, blower motor, rear window defroster) on and 
verify that the voltage reading increases.

CAUTION:



Do not apply direct battery positive voltage to the generator terminal 
D, otherwise it could cause damage to the internal parts (power 
transistor) of the generator.  

 

2008 Mazda MX-5 Miata Grand Touring 

2008 ELECTRICAL Charging System - MX-5 Miata

  

Fig. 8: Identifying Ignition Switch Connector Terminals 
Courtesy of MAZDA MOTORS CORP. 

Current 

1. Verify that the battery is fully charged.  

2. Verify that the drive belt deflection/tension is correct. (See DRIVE BELT INSPECTION [LF] .)  

3. Disconnect the negative battery cable.  

4. Connect a tester, which can read 120 A or more , between generator terminal B and the wiring harness.  

5. Connect the negative battery cable. (See BATTERY REMOVAL/INSTALLATION [LF] .)  

6. Turn off all electrical loads.  

7. Start the engine.  

8. Increase engine speed to 2,500 rpm. 

NOTE:



Since the charging current decreases rapidly after starting the engine, 
carry out the following procedure quickly, and read the maximum current 
value.  

NOTE:



When the electrical load of the vehicle is low, the specified current 

 

2008 Mazda MX-5 Miata Grand Touring 

2008 ELECTRICAL Charging System - MX-5 Miata