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Steve
Steve, Auto Service Technician
Category: Car
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Experience:  25+ yrs experience as a professional working technician; ASE L1 master technician
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High voltage..I replaced battery and alternator 5/16/05..volts

Customer Question

I keep getting high voltage on my d.i.c. I replaced battery and alternator 5/16/05 still reading 16.2 volts
to 13.8 no ryme or reason .....error code 16
Submitted: 11 years ago.
Category: Car
Expert:  Steve replied 11 years ago.

 Kelly;


   As far as I am aware and can tell from the wiring schematics and trouble cose diagnostics for a code E016, the only hting that can cause an overcharging problem here is a defective voltage regulator (inside the alternator).


   You may want to be aware, that charging voltage under normal operation may reach 15.9 volts at times.  Voltage over 16V sets the code and turns on the 'service engine" light.


   Sounds like you may ahve another defective alternator here, although the regulator is replaceable separately if the alternator isnt under warranty any longer.


   Most auto parts stores can bench test an alternator for you if you take it off and bring it in to them.  They connect it to a motor and spin int, and take measurements of voltage, amperage, and ripple output.

Steve, Auto Service Technician
Category: Car
Satisfied Customers: 5494
Experience: 25+ yrs experience as a professional working technician; ASE L1 master technician
Steve and 9 other Car Specialists are ready to help you
Customer: replied 11 years ago.
Reply to Steve Rapp's Post: Questionable answer as the alternator i took off performed exactly the same.
Expert:  Steve replied 11 years ago.

 kelly;


   I reviewed the service manual information for the charging system and it shows all regulator circuits inside the alternator; tehre is nothing external on this unit that can cause an overcharging problem...    The component that controls charging voltage by switching the alternator field circuit off and on is a solid state component located in the rear housing of the alternator with no external wiring to fail...


   Did your replacement alternator work OK for a while?   Regulator failure was a common problem on GM alternators before modern computer controlled charging systems came on the market; I used to stock several regulators in our shop back when rebuilding alternators in teh field was a common everyday procedure.


   Regulators can be damaged by voltage spikes or large current surges.    Is it possible it was damaged recently?  A very common way of damaging electronic components is through jump starting .   Disconnecting battery chargers or battery terminals with the key accidentally left on is another common cause of momentary voltage spikes.


   If there is a 2 wire flatwhite plastic plug going to this alternator, that plug is connected directly to the regulator to supply power to it from teh ignition switch; examine the plug closely looking for darkened plastic or damaged terminals that might indicate overheating of the conenction; if it is damaged or queationable, replacing teh plug when teh alternator is replaced might be a good idea; tehya re cheap and easy to install.


   Hope this is helpful; if it is indeed overcharging, i am confident that a bench test will show the unit to be out of spec.  It should be under warranty if it is still fairly new.


   If I can be of any further assistance, please feel free to ask;


Thanks!

Expert:  Steve replied 11 years ago.
 The CS charging system has several sizes available, including the CS-121, CS-130 & CS-144 alternators. The number (121, 130 or 144) denotes the outside diameter in millimeters (mm) of the stator laminations.
CS generators use a new type regulator and a diode trio is not used. A delta stator, rectifier bridge, and rotor with slip rings and brushes are electronically similar to earlier generators. A conventional pulley and fan is used and, on the CS-130, an internal fan cools the slip ring end frame, rectifier bridge and regulator.
Unlike three wire generators, the CS generators may be used with only two connections, battery positive and an "L" terminal to the charge indicator bulb.
Use of the "P", "F", and "S" terminals is optional. The "P" terminal is connected to the stator, and may be connected externally to a tachometer or other device. The "F" terminal is connected internally to field positive, and may be used as a fault indicator. The "S" terminal may be connected externally to a voltage, such as battery voltage, to sense voltage to be controlled.
As on other charging systems, the charge indicator lights when the switch is closed, and goes out when the engine is running. If the charge indicator is on with the engine running, a charging system defect is indicated. For all kinds of defects, the indicator will be on with the engine running if system voltage is too high or too low. The regulator voltage setting varies with temperature, and limits voltage by controlling rotor field current.
This regulator switches rotor field current on and off at a fixed frequency of about 400 cycles per second. By varying the on-off time, correct average field current for proper system voltage control is obtained. At high speeds, the on time may be 10% and the off time 90%. At low speeds, with high electrical loads, on and off time may be 90% and 10%, respectively.
No periodic maintenance on the generator is required. The CS-121 and CS-130 are not repairable and may only be replaced as a single unit. The CS-144 is repairable.





Alternator testing procedure:







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  1. Visually check belt and wiring and make necessary repairs.
  2. With ignition switch in RUN position and engine stopped, the charge indicator lamp should be on. If it is not on, disconnect harness at generator and ground negative terminal in harness with a fused jumper lead. If lamp lights, replace generator. If lamp does not light, locate open in circuit between ignition switch and harness connector and check for burned out indicator lamp.
  3. With ignition switch in RUN position and engine running at a moderate speed, the charge indicator lamp should be off. If it is not off, disconnect harness at generator. If lamp goes off, replace generator. If lamp stays on, check for a short to ground in harness between connector and indicator lamp.
  4. Check battery for an overcharged or undercharged condition as follows:



    1. Attach a suitable voltmeter, ammeter and carbon pile to vehicle.
    2. With ignition switch in OFF position, check and record battery voltage.
    3. Remove harness connector from generator.
    4. Turn ignition switch to Run position and check voltage at the brown wire in harness. Battery voltage should be present. If battery voltage is not present, check charge indicator circuits for open or grounded circuits causing voltage loss and repair as necessary.
    5. Reconnect generator harness connector.
    6. Run engine at a moderate idle and measure voltage across battery terminals. Voltage should read more than recorded in step B and less than 16 volts. If reading is not as specified, replace generator.
    7. Run engine at a moderate idle and check generator amperage output. Adjust carbon pile load to obtain maximum amperage while maintaining battery voltage above 13 volts. If amperage reading is within 15 amps of generators rating, generator is functioning properly. If amperage is not within 15 amps, replace generator.
    8. With generator operating at maximum output, measure voltage between generator housing and battery negative terminal. Voltage drop should be .5 volt or less. If more than .5 volt, check ground path from generator housing to battery negative and determine cause of voltage drop. Repair loose or corroded ground connections as necessary.




 







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