Holley 550-407, Installation Manual, Page: 51 / 54

51
APPENDIX 2.0 SENSOR DIAGNOSTICS AND STATUSES
Sensor diagnostics are included in the handheld. If one of the main sensors has some type of error, a small, blinking red circle will appear
in the upper right of the screen. To navigate to the diagnostics, select MONITOR and DIAGNOSTICS. If there is an issue, an error will
also be shown on any of the MONITOR or GAUGES screens.
Wideband Oxygen Sensor Status
–
Shows status of wideband oxygen sensors.
Text Description
…
Signifies that sensor channel is not enabled.
Init.. First shown for an instant when the system is powered on. Displayed so quickly you will likely not see this.
Heating Sensor is heating.
Cold! Sensor is below calibrated operating temperature. Unit will still read but accuracy may be impacted.
Hot! Sensor is above calibrated operating temperature. Unit will still read but accuracy may be impacted.
Unplgd Sensor is unplugged.
General Sensor Status
–
These are shown for the coolant and air temperature, MAP, TPS, Oil and Fuel pressure sensors. If you do not
have an oil or fuel pressure sensor installed, you will see this error. It will not cause a problem.
Text Description
Undefnd Unlikely failure indicated that a sensor is not properly defined.
LOW
Err
A sensor displaying this can be unplugged, have an open or short circuit, or be otherwise damaged.
HI Err A sensor displaying this can be unplugged, have an open or short circuit, or be otherwise damaged.
RPM (Crank Signal Inputs) Diagnostics
– The following are shown for the “RPM” parameter which indicates the status of the crank
sensor/engine speed input.
Text Description
Stall! No RPM input detected.
Syncng Signal detected. Position being established.
Nothing Will show briefly after crank signal and cam/crank positions established. Actual engine RPM will then be
indicated.
Error! Cam/Crank input error detected.
TPS Diagnostics
– The following are shown for the “TPS” parameter.
Text Description
Error! If you see an error, contact Holley Tech Service.
NeedCal TPS Autoset needs to be performed.
Closed Loop Diagnostics
–
Shows status of closed loop operation.
Text Description
OpenLp System is in open loop operation.
CloseLp System is in closed loop operation.
Learn Status
–
Shows status of learn mode.
Text Description
NoLearn Learning is not active.
Learng
Learn is in an active state.
Switched Inputs/Outputs Status
–
Shows status of switched inputs and outputs.
Text Description
OFF Input or Output is not active.
ON Input or Output is active.