TEST A VOLTAGE REGULATOR ON A 30KW GENERATOR - Generac 13,000 Watt / 13,000 Watt Home Standby Generator

DTC P1637

The powertrain control module (PCM) / engine control module (ECM) uses the charge indicator control circuit, and the generator 2 turn on signal circuit on diesels with dual generators, to control the generator(s). A high side driver within the PCM/ECM allows the PCM/ECM to turn the generator ON and OFF. When generator operation is desired, the PCM/ECM sends a 10-11 volts-volt signal to the voltage regulator via the generator turn on signal circuit. This causes the voltage regulator to begin controlling the generator field circuit. Once the generator is enabled by the PCM/ECM, the voltage regulator controls generator output independently of the PCM/ECM. Under certain operating conditions, the PCM/ECM can turn OFF the generator by turning OFF the voltage on the charge indicator control circuit. The PCM/ECM has fault detection circuitry which monitors the state of the charge indicator control circuit. If the fault detection circuit senses a voltage other than what is expected, the charge indicator will turn ON and this DTC will set. The voltage regulator also contains fault detection circuitry. If the regulator detects a problem, the regulator will ground the charge indicator control circuit, pulling the voltage low. This also causes the charge indicator to turn ON and the PCM/ECM to set the DTC.

What engine is in your truck ?

DTC P1638

The powertrain control module (PCM) uses the generator field duty cycle signal circuit to monitor the duty cycle of the generator. The generator field duty cycle signal circuit connects to the high side of the field winding in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field winding ON and OFF. The PCM uses the PWM signal input to determine the generator load on the engine. This allows the PCM to adjust the idle speed to compensate for high electrical loads.
The PCM monitors the state of the generator field duty cycle signal circuit. When the key is in the RUN position and the engine is OFF, the PCM should detect a duty cycle near 0 percent. However, when the engine is running, the duty cycle should be between 5-100 percent. The PCM monitors the PWM signal using a key ON test and a RUN test. During the tests, if the PCM detects an out of range PWM signal, DTC P1638 will set. When the DTC sets, the PCM will send a class 2 serial data message to the IPC to illuminate the charge indicator.

Around 15 + or - a little. This indicates the alternator is charging.

The red wire from starter, at the alternator, hot all the time. The orange wire at alternator, hot all the time. Use a test light on those wires, if hot, I don't think it is a fuse? Your owners manual should have the fuse layout.

Running the car will drain the battery it if it's not charging ! An if your charging light is on it isn't charging ! Did you check power an grounds on the alternator ? There is a single heavier wire on the back of the alternator, this should have battery voltage ! You may want to take this to a ASE certified repair shop !
Functionality
With the ignition switch in the RUN position, voltage is applied through the warning indicator I circuit 904 (LG/RD) to the voltage regulator. This turns the regulator on, allowing current to flow from battery sense A circuit 35 (OG/LB) to the generator field coil. When the engine is started, the generator begins to generate alternating current (AC) which is internally converted to direct current (DC). This current is then supplied to the vehicle's electrical system through the output (B+) terminal of the generator.
Once the generator begins generating current, a voltage signal is taken from the generator stator and fed back to the regulator S circuit 4 (WH/BK). This voltage feedback signal (typically half the battery voltage) is used to turn off the warning indicator.
With the system functioning normally, the generator output current is determined by the voltage of the A circuit 35 (OG/LB). The A circuit 35 (OG/LB) voltage is compared to a set voltage internal to the regulator, and the regulator controls the generator field current to maintain the correct generator output.
The set voltage will vary with temperature and is typically higher in cold temperatures and lower in warm temperatures. This allows for better battery recharge in the winter and reduces the chance of overcharging in the summer.
Battery Positive Output (B+) Circuit 38 (BK/OG)
The generator output is supplied through the battery positive output (B+) terminal on the back of the generator to the battery and electrical system.
I Circuit 904 (LG/RD)
The I (ignition) circuit 904 (LG/RD) is used to turn on the voltage regulator. This circuit is powered up with the ignition switch in the RUN position. This circuit is also used to turn the charging system warning indicator on if there is a fault in the charging system operation.
A Circuit 35 (OG/LB)
The A (battery sense) circuit 35 (OG/LB) is used to sense battery voltage. This voltage is used by the regulator to determine generator output. This circuit is used to supply current to the generator field (rotor). The amount of current supplied to the rotor will determine generator output.
S Circuit 4 (WH/BK)
The S (stator) circuit 4 (WH/BK) is used to feed back a voltage signal from the generator to the regulator. This voltage is used by the regulator to turn off the charging system warning indicator. The S circuit is fed back externally on external mounted regulator generators.
Visual Inspection Chart Mechanical Electrical

• Battery case, posts, hold-down clamp, cables and connections
• Generator drive (serpentine) belt for condition and tension to make sure there is no slip between the belt and the pulley. For additional information, refer to Section 303-05 .
• Battery charge
• Generator pulley

• Battery junction box (BJB)Mega Fuse
• Battery junction box fuse:
  • 11 (20A)
• Central junction box (CJB) fuse:
  • 30 (30A)
• Circuitry
• Charging system warning indicator
• Cables

1. Check the operation of the charging system warning indicator lamp (instrument cluster). Normal operation is as follows:
   • With the ignition switch OFF, the charging system warning indicator should be OFF.
   • With the ignition switch in RUN and the engine off, the charging system warning indicator light should be on.
   • With the engine running, the charging system warning indicator light should be off.

1. Verify the battery condition. Refer to Section 414-01 .

Normal Charging System Voltages and Charging System Warning Indicator Operation Ignition Switch Position A Circuit 35 (OG/LB) S Circuit 4 (WH/BK) I Circuit 904 (LG/RD) Generator B+ Circuit 38 (BK/OG) Battery Engine to Battery Ground Charging System Warning Indicator Operation OFF 12 volts 0 volts 0 volts 12 volts 12 volts 0 volts Off RUN-engine off 12 volts 0 volts 1-3 volts 12 volts 12 volts 0 volts Illuminated RUN-engine running 13-
15 volts 1/2 battery voltage 13-
15 volts 13-
15 volts 13-
15 volts 0 volts Off

1. If the customer concern is verified after the initial inspection, refer to the Symptom Chart to determine which tests to carry out.
2. • The charging system warning indicator is on with the engine running (the system voltage does not increase)
   • Circuitry.
   • Voltage regulator.
   • Generator.
   • GO to Pinpoint Test B .
   Your whole problem is the alternator is not charging , a couple tests with a volt meter would tell you !

test the battery voltage while the engine is running, (you'll have to jump it again)
if you know the battery, voltage regulator and alternator are good, you may have to check all the fuse-able links on the car, all the vehicle grounds, and the fuses and relays.
if you put your battery on charge until it is fully charged and let the car sit over night and it is dead, either the battery is internally shorted or the vehicle is drawing far to much current and each circuit tested to find the short.

The UV code has nothing to dow ith oil, poor oil would cause under frequency (low engine speed) Under voltage is caused by excessive load, short in the rotor/stator excition system, and/or AVR automatic voltage regulator. Of course loose wiring to will also cause it.

Sounds like you fried it. 17VDC is way over the limit of 15.5VDC and you may have also over heated your battery. Check the battery water level and if ok, have the battery load tested. Generator may be under warranty, if you don't tell them about the bad regulator, but since they probably supplied both, give it a try anyway. Also have the one on your VW tested off the car and if they can also the regulator. Would be a good idea to also check your wiring for broken wires between the regulator and generator.

If the charging light is on in your 1979 Harley Davidson XLH 1000 Sportster, it indicates a potential issue with the charging system. Here are some steps you can take to check for the problem:

1. Battery Check: Begin by checking the battery voltage using a multimeter. Ensure that the battery is fully charged, and its voltage is within the recommended range specified in the owner's manual.
2. Belt Tension: Examine the belt tension of the generator drive belt. If it is loose or worn, it may not be driving the generator properly. Adjust or replace the belt if necessary.
3. Wiring Inspection: Carefully inspect the wiring connections between the generator, voltage regulator, and battery. Look for loose connections, damaged wires, or corroded terminals. Ensure all connections are clean, secure, and properly connected.
4. Voltage Regulator Check: Test the voltage regulator using a multimeter. With the motorcycle running, measure the voltage output at the battery terminals. It should be within the recommended range specified in the owner's manual. If the voltage is too high or too low, it may indicate a faulty voltage regulator.
5. Generator Output Test: To check the generator output, you will need a multimeter capable of measuring AC voltage. Disconnect the generator output wire from the voltage regulator and start the motorcycle. Set the multimeter to measure AC voltage and connect the leads to the generator output wire and a good ground. The reading should be within the specified range mentioned in the owner's manual. If there is no or low voltage output, it may indicate a faulty generator.
6. Fuse Inspection: Check the fuses related to the charging system. Ensure they are not blown or damaged. Replace any faulty fuses with the appropriate rating.

If you are unable to diagnose or resolve the charging system issue using these steps, it is recommended to consult a qualified motorcycle mechanic or contact an authorized Harley-Davidson dealership for further assistance. They will have the expertise and experience to diagnose and repair the specific charging system problem in your 1979 Harley Davidson XLH 1000 Sportster.

Generator with Integral Rear Mount Voltage Regulator, Internal Fan Type With the key in the RUN position, voltage is applied through the charge indicator lamp I circuit to the voltage regulator. This turns the voltage regulator on, allowing current to flow from the battery sense A circuit to the generator field coil. When the engine (6007) is started, the generator (GEN) (10346) begins to generate alternating (AC) current which is converted to direct (DC) current by the rectifier internal to the generator. This current is then supplied to the vehicle's electrical system through the battery positive voltage (B+) terminal located on the rear of the generator. Once the generator begins generating current, a voltage signal is taken from the stator and fed back to the voltage regulator S circuit, turning off the charge indicator/lamp. With the system functioning normally, the generator output current is determined by the voltage at the A circuit. This voltage is compared to a set voltage internal to the voltage regulator, and the voltage regulator controls the generator field current to maintain proper generator output. The set voltage will vary with temperature and is typically higher in the winter than in the summer, allowing for better battery recharge. With the system functioning normally, the generator output current is determined by the voltage of the A circuit (battery sense voltage). The A circuit voltage is compared to a set voltage internal to the voltage regulator, which controls the generator field current to maintain proper output. The set voltage will vary with temperature and is typically higher in the winter than in the summer, allowing for better battery recharge in the winter and reducing the chance of overcharging the battery in the summer. A fuse link is included in the charging system wiring on all vehicles. The fuse link is used to prevent damage to the wiring harness and generator if the wiring harness should become grounded, or if a booster battery with the wrong polarity is connected to the charging system. Mitsubishi 215-Ampere Generator
The Mitsubishi 215-ampere generator is an internally regulated, brushless unit that is self-current limiting and temperature compensating. The regulator is integral with the generator and the fan is external.

VISUAL INSPECTION CHART Mechanical Electrical

• Before attempting to test a battery, it is important to give it a thorough examination to determine if it has been damaged.

• Batteries are tested to determine the state of charge and ability to crank an engine. The result of these tests is to show that the battery is either good, needs recharging, or must be replaced.

• Preliminary checks to the charging system should be made regardless of the fault condition. These checks include:
  • Check the fuses/fuse links to the generator to ensure that they are not burned or damaged. This condition, resulting in an open circuit or high resistance, can cause erratic or intermittent charging system concerns.
  • Check battery posts and cable terminals for clean and tight connections. Clean the posts and the cables to ensure good electrical contact.
  • Check for secure connections at the generator output, voltage regulator and engine ground. Also check the connection at the power distribution point.
  • Check the generator drive belt to ensure proper tension and no slip between the generator pulley and the drive belt. Refer to Section 03-05 in the Powertrain, Drivetrain Manual.
  • Check battery for full charge.

• Before performing charging system tests on the vehicle, note conditions such as: slow cranking, discharged battery, charge indicator lamp stays on with engine running, charge indicator lamp does not illuminate with ignition switch in RUN and engine not running, etc. This information will aid in isolating the part of the system causing the symptom.
• When a relatively new battery is discharged, test for current drain. The following are some of the most common current drain concerns:
  • Glove compartment lamp stays on with the door closed.
  • Engine compartment lamp stays on constantly.
  • License plate lamp or interior lamp stays on constantly.
  • Other electronic component concerns.

not cpu.
Do not field out the field wire.
Is the alternator ight coming on?
If you rev engine, does charging system start working?
There is a resister wire that provides voltage to the field circuit. If the resister is bad, you will only get voltage to the field through the dash alt. light bulb when you push enough voltage through it.

I don''t have 1993, but here is 96:

Generator with Integral Rear Mount Regulator, Internal Fan Type With the key in the RUN position, voltage is applied through the charge indicator lamp I circuit to the voltage regulator. This turns the voltage regulator on, allowing current to flow from the battery sense A circuit to the generator field coil. When the engine (6007) is started, the generator (GEN) (10346) begins to generate alternating (AC) current which is converted to direct (DC) current by the rectifier internal to the generator. This current is then supplied to the vehicle's electrical system through the battery positive voltage (B+) terminal located on the rear of the generator. Once the generator begins generating current, a voltage signal is taken from the stator and fed back to the voltage regulator S circuit, turning off the charge indicator/lamp. With the system functioning normally, the generator output current is determined by the voltage at the A circuit. This voltage is compared to a set voltage internal to the voltage regulator, and the voltage regulator controls the generator field current to maintain proper generator output. The set voltage will vary with temperature and is typically higher in the winter than in the summer, allowing for better battery recharge. With the system functioning normally, the generator output current is determined by the voltage of the A circuit (battery sense voltage). The A circuit voltage is compared to a set voltage internal to the voltage regulator, which controls the generator field current to maintain proper output. The set voltage will vary with temperature and is typically higher in the winter than in the summer, allowing for better battery recharge in the winter and reducing the chance of overcharging the battery in the summer. A fuse link is included in the charging system wiring on all models. The fuse link is used to prevent damage to the wiring harness and generator if the wiring harness should become grounded, or if a booster battery with the wrong polarity is connected to the charging system.
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• System Does Not Charge

• Loose or worn drive belt.
• Open/voltage drop in Circuit 38 (BK/O).
• Open/voltage drop in Circuit 36 (Y/W).
• Open/high resistance in Circuit 904 (LG/R).
• Damaged regulator.
• Damaged generator battery