P1257

Description
SUPERCHARGER SYSTEM OVERBOOST

Normally PCM commands Boost Control (BC) solenoid to operate
at 100 percent (ON) Pulse Width Modulation (PWM) to allow for full
intake boost upon demand. If Reverse is selected, PCM detects rapid
deceleration, or engine is load is extremely high, PCM commands BC
solenoid to operate at zero percent (OFF) PWM.

Symptoms
You likely won't notice any drivability problems.

Causes

• Engine torque exceeds maximum predetermined torque threshold
  value.

Solutions

• Check for restriction in boost signal hose between BC
  solenoid and supercharger by-pass valve actuator.
• Check for binding by-pass valve, sticking or misadjusted
  by-pass valve actuator linkage.
• Replace by-pass valve actuator.
• Check for restriction in boost source hose to BC
  solenoid.
• Check for faulty connections or damaged harness.