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P0621 Suzuki Code - Generator Lamp L Control Circuit Malfunction

- Code Popularity: 3,365 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P0621 Suzuki?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Battery charge
  • Faulty Generator
  • Generator harness is open or shorted
  • Generator circuit poor electrical connection
  • Engine Control Module (ECM) controlled generator
  • Faulty ECM
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How to Fix the DTC P0621 Suzuki?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

The ECM/PCM is detecting a high turn-on voltage at times. Possible causes could be the alternator or the ECM/PCM.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0621 Suzuki code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

When is the Code Detected?

The Engine Control Module (ECM) has fault detection circuitry which monitors the state of the generator turn on signal circuit. If the fault detection circuit senses a voltage other than what is expected, this P0621 code will set. The voltage regulator also contains fault detection circuitry. If the regulator detects a problem, the regulator will ground the generator turn on signal circuit, pulling the voltage low. This also causes the ECM to set the P0621 code.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

Code P0621 Suzuki Description

The Engine Control Module (ECM) uses the generator turn on signal circuit to control the generator. A high side driver within the ECM allows the ECM to turn the generator ON and OFF. When Generator operation is desired, the ECM sends a 5 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 ECM, the voltage regulator controls generator output independently of the ECM. Under certain operating conditions, the ECM can turn Off the generator by turning Off the 5 volt signal on the generator turn on signal circuit.
OBDII Code P0621 Suzuki - Generator Lamp L Control Circuit Malfunction - AutoCodes.com
P0621 Suzuki Code - Generator Lamp L Control Circuit Malfunction

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