P1558

DTC P1558 Flow Chart:

Cruise Control Servo Wiring Schematic:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) controlled cruise control system is designed to monitor itself to be sure that the desired cruise position and actual cruise position are equal to each other. If the actual servo position is too low when maximum servo position is commanded, the PCM will set Diagnostic Trouble Code (DTC) P1558.

DTC P1558 WILL SET WHEN
^ Throttle angle less than 50%.
^ Desired servo pos. is 90%.
^ Actual servo position is less than 2%.
^ Above condition for 3 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
The PCM will disengage cruise control if a current DTC P1538 is set and cruise control set speed exceeds vehicle speed by more than 5 mph. DTC P1558 does not illuminate the Malfunction Indicator Lamp (MIL).

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test checks the Servo Position Sensor (SPS). If the SPS signal is not being received correctly at the PCM, the DTC P1565 chart should be used to diagnose the condition.
2. This test verifies that the vacuum portion of the cruise system is operational.
3. Checks for a faulty brake switch. If the resistance of the brake switch is too high, the cruise vent and vacuum solenoids will not operate correctly, resulting in a cruise control inoperative condition and DTC P1558.

DIAGNOSTIC AIDS
A cruise control throttle cable which binds or intermittently sticks can cause DTC P1558 to set. Outside interference such as a CB antenna lead near the PCM wiring harness may induce a false SPS signal and set DTC P1558.

An intermittent may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation.

Check for poor connections or a damaged harness - Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.