Aug 302018

2012 Hyundai Sonata Hybrid

I have code p1777, PCM out put malfunction.
Where I can start to check? What that code means?
thank you

Code P1777 – OPU Power Control Circuit Failure

Code P1777 is set and sent to the PCM/TCM when OPU detect error into OPU internal power control circuit.

Possible Causes:

  1. OPU Power stack error
  2. EOP stuck error
  3. 3-phase wiring short to VB,GND

OPU Power Control Unit Location

OPU Power Control Unit Location

Code P1777 General Description

The HEV uses the hydraulic pressure that in addition to mechanical main hydraulic pump EOP (Electric oil pump) controlled by OPU (oil pump unit) to take command by PCM/TCM generates oil pressure to operate clutch and U/D brake.

When low speed driving or engine auto stop regardless of driving mode (EV mode or HEV), when hydraulic pressure becomes low because of mechanical main hydraulic pump rotation in low speed or stop, OPU supplies hydraulic pressure on U?D brake by operating EOP in order to protect Friction Element.

When shifting the driving mode from EV mode to HIV mode, EOP supplies hydraulic pressure to the engine clutch in order to use engine power when the driving mode shift is completed (Engine clutch: wet type multiple disk clutch that connect or disconnect the engine power between engine input shaft and transaxle input shaft)

What to check

According to the Manual you are to inspect the terminal and connectors first. Then check the component itself.

  • Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration or damage.
  • In order to check the component, the manual advises to clear the code(with a scantool) after cycling the IG on and off two or three times. If the same code returns, substitute with a known-good PCM/TCM and check for proper operation. If the problem is corrected, replace PCM/TCM.

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