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DTC codes / P21xx · Fuel and air metering / P216B

P216BFuel Injector Group E Supply Voltage Circuit Low

P216B indicates that the powertrain control module (PCM) has detected a low voltage condition on the power supply circuit for fuel injector group E. This group typically includes multiple injectors that share a common power feed, and the PCM monitors the circuit for voltage below a calibrated threshold, which can affect fuel delivery and engine performance.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Illuminated check engine light (malfunction indicator lamp) with no other noticeable symptoms.
  • Rough idle or misfire, especially noticeable when the engine is cold or under load.
  • Hesitation or stumble during acceleration due to one or more injectors in the group not firing.
  • Reduced engine power or limp mode in some vehicles as a protective measure.
  • Poor fuel economy or increased emissions due to improper fuel delivery.
  • In rare cases, the engine may stall or be difficult to start if multiple injectors are affected.

Common causes, most likely first

  1. A damaged or corroded wire in the injector group E power supply circuit, such as a chafed wire or broken connector.
  2. A faulty fuel injector in group E with an internal short or open coil that drags down the supply voltage.
  3. A blown fuse or faulty relay that supplies power to the injector group, though this often affects multiple groups.
  4. High resistance in a connector or ground point shared by the injector group, leading to voltage drop.
  5. A malfunctioning powertrain control module (PCM) driver circuit for the injector group, though this is less common.
  6. Corrosion or water intrusion in the wiring harness or connectors, especially in areas exposed to the elements.

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related codes in other systems to narrow down the circuit.
  2. Inspect the wiring harness and connectors for the injector group E for signs of damage, corrosion, or loose pins.
  3. Check the fuse and relay that supply power to the injector group, replacing them if necessary.
  4. Measure the resistance of each injector in group E and compare to specifications to identify a faulty injector.
  5. Perform a voltage drop test on the power supply circuit to locate excessive resistance in wires or connectors.
  6. If the circuit and injectors test good, suspect the PCM and perform further diagnostics before replacement.
  7. Clear the code and test-drive the vehicle to confirm the repair, monitoring live data for injector pulse width and voltage.

What Most Techs Overlook on P216B

  • A low voltage code for an injector group often stems from a poor ground connection rather than a faulty injector, so always check ground points first.
  • The injector group letter (E) does not correspond to a specific cylinder; it is a grouping defined by the manufacturer, so consult the service manual for the exact injectors involved.
  • A weak battery or charging system can cause low voltage codes across multiple circuits, so verify battery and alternator health before chasing injector wiring.
  • Intermittent faults may only appear when the engine is hot or vibrating, so wiggle-test the harness while monitoring live data to catch a bad connection.
  • Replacing an injector without checking the supply voltage can lead to a repeat failure if the root cause is a shorted wire or corroded connector.

Can I keep driving with P216B?

Driving with P216B is generally safe for short distances, but avoid heavy acceleration or towing until the fault is repaired. Prolonged driving with a misfire can damage the catalytic converter, so schedule service promptly if symptoms are present.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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