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DTC codes / P21xx · Fuel and air metering / P215E

P215EReductant Heater D Current Too Low

P215E indicates that the powertrain control module (PCM) has detected an abnormally low current draw in the electrical circuit for the reductant heater 'D', which is one of the heating elements used to keep diesel exhaust fluid (DEF) from freezing. The PCM monitors the current through the heater circuit and sets this code when the measured current falls below the expected threshold for the given conditions.

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

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms.
  • A pending or stored P215E code may be the only sign if the ambient temperature is above freezing.
  • In cold weather, the vehicle may enter a reduced power or limp mode due to DEF not being heated properly.
  • Possible poor DEF dosing performance leading to increased emissions or frequent regeneration cycles.
  • In some cases, a message on the driver information center indicating DEF system fault or service required.
  • Rough running or hesitation if the reductant system cannot maintain proper injection quantity.

Common causes, most likely first

  1. Open or high-resistance wiring in the reductant heater D circuit, such as a broken wire or corroded connector.
  2. Failed reductant heater element D, causing an open circuit or excessive resistance.
  3. Blown fuse or faulty relay that supplies power to the reductant heater D.
  4. Poor ground connection for the heater circuit, leading to low current flow.
  5. Faulty PCM driver for the heater circuit, though this is less common.
  6. Contamination or damage to the heater connector pins from DEF crystallization or corrosion.

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related codes in the reductant system.
  2. Inspect the reductant heater D circuit wiring and connectors for obvious damage, corrosion, or loose pins.
  3. Check the fuse and relay that supply power to the reductant heater D and replace if faulty.
  4. Measure the resistance of the reductant heater D with a multimeter and compare to the manufacturer's specification; replace the heater if out of range.
  5. Perform a voltage drop test on the power and ground sides of the heater circuit to identify excessive resistance.
  6. If all electrical checks pass, test the PCM output for the heater control circuit and repair or replace the PCM as needed.
  7. Clear the codes and perform a road test or actuator test to confirm the repair.

Reductant heater D current diagnostics

  • A common oversight is assuming the heater element itself is always at fault, but corroded connectors or chafed wiring often cause low current without a failed heater.
  • The code can be set by a weak battery or charging system issue that reduces available voltage to the heater circuit, so always check battery condition first.
  • Some vehicles use multiple reductant heaters (A, B, C, D) and a single fault in one heater can trigger other related codes; focus on the specific circuit for P215E.
  • After repairs, the PCM may require a relearn or adaptation reset for the reductant system to clear the code and restore normal operation.
  • In freezing conditions, the heater may not activate until certain criteria are met, so the code might only set during specific temperature windows, making intermittent diagnosis tricky.

Can I keep driving with P215E?

You can usually continue driving with P215E, but avoid long trips in freezing temperatures because the DEF may not heat properly, leading to reduced engine power or emissions system faults. Have the vehicle inspected soon to prevent more serious reductant system damage.

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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