VOLVOUU All Engines (2010 Emissions) Fault Code: SPN 188 FMI 1 PID: Engine Speed at Idle, Point 1

The Engine Control Module (ECM) monitors the crankshaft angular acceleration using the flywheel sensor. The ECM monitors the camshaft position sensor to determine the engine?s position. The ECM calculates the average value of crankshaft angular acceleration for all six cylinders and compares the value to each individual cylinder?s angular acceleration. If a cylinder?s acceleration value is outside a specified range the ECM interprets this as a misfiring cylinder. The crankshaft average angular acceleration value is used by the ECM to determine cylinder balancing and idle speed.

Conditions for diagnostic trouble code (DTC):
1) Engine Speed at idle, Below normal

Observable symptoms
1) Idle Below normal

Probable cause
1) Power Take Off (PTO) installed without updating parameters and/or software
2) Parameter code, unit injector
3) Fuel
4) Injector
5) Low compression