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U0599 — Invalid Data Received From Dcdc Converter Control Module

Generic OBD-II · all makesNetwork / communication

U0599 indicates the Powertrain Control Module (PCM) has received data from the DC-DC converter control module that does not meet the expected format or checksum. This communication error prevents the PCM from using the converter’s voltage regulation information.

Symptoms

What causes it — most likely first

1. Faulty DC-DC converter control module

Internal failure of the converter’s control electronics can corrupt the data it sends to the PCM.

2. Corroded or damaged wiring harness between DC-DC converter and PCM

Excessive corrosion, broken pins, or frayed wires can alter or interrupt the signal.

3. Loose or poorly seated connector at the DC-DC converter

Vibration or prior removal can cause a connector to lose proper contact, resulting in bad data.

4. Voltage spike or grounding issue affecting the communication bus

Transient spikes or a bad ground can cause checksum errors on the data stream.

5. PCM communication software glitch (rare)

Only after ruling out the converter and wiring should the PCM’s firmware be considered for re‑flash or replacement.

How it's diagnosed

  1. Use a scan tool to view live data from the DC-DC converter and verify voltage output ranges.
  2. Inspect the wiring harness and connectors for corrosion, damage, or loose pins; repair as needed.
  3. Perform a continuity and resistance check on the communication lines to ensure they meet spec.
  4. Apply a known‑good DC-DC converter (or bench test the existing unit) to see if the code clears.
  5. If all hardware checks are satisfactory, update the PCM firmware or perform a re‑flash as a last resort.

Code facts & related codes

SystemNetwork / communication
StandardizationSAE generic — identical on every make
Related codesU0592 — Invalid Data Received From Gear Shift U0593 — Invalid Data Received From Drive MotorU0594 — Invalid Data Received From Hybridev PoU0595 — Invalid Data Received From Powertrain U0596 — Invalid Data Received From Acac ConverU0597 — Invalid Data Received From Acdc Conver

Frequently asked

Do I need to replace the PCM to fix U0599?

In most cases no. The PCM is usually receiving bad data because of a problem with the DC-DC converter, its wiring, or a grounding issue. Replace the PCM only after all other possibilities have been eliminated.

Will a battery replacement clear this code?

Replacing the battery alone will not fix U0599 unless the old battery was causing extreme voltage spikes that damaged the converter or wiring.

Can a simple software update resolve the issue?

A PCM software update can sometimes correct communication timing errors, but it should be performed only after confirming that the converter and its connections are functioning correctly.

Is the DC-DC converter a safety‑critical component?

Yes. It regulates the voltage supplied to low‑voltage vehicle systems, so a failure can affect lighting, electronics, and hybrid/EV operation.