Attention: TDR Forum Junkies 
Outrigth CP-3 failures are rare given service and fuel quality is observed. However, they can fail in increments and cause codes and symptoms that are not exactly definitive of a failed pump.
Example; oil in the fuel. Bad injctgors is the first thing that comes to mind because it is the most common. However, the CP-3 has a seal that keeps lube and cooling fuel from leaking into the front cover. A weeping CP-3 is common in colder weather because of the componenet sparts and different expansion rates. However, it could be the seal starting to go on the shaft and leaking out a hard to see weep hole.
Example; low power and high EGT's under load mean a fuel delivery problems. Will run fine empty and no codes present but it doesn't run well. Could be the FCA sticking, COV weak, low LP delivery flow, or the pump itself is toast.
In both cases you have to start verifying th ebasics, filter, fuel flow, obvious leaks. Then the fun starts. Look for codes and with a scanner capable of seeing everything. Some DTC's will not set a CEL and not be seen by cheap readers. A fuel pressure gauge that can be tapped at the CP-3 inlet and a CTS to read parameters are a good start for basic tools.
P0148 High Pressure Common Rail (HPCR) Fueling Error Checksum
P0251 CP3 Pump Regulator Control
Two of the most common with many sources, from bad sensor to bad connection to bad battery or connections to low fuel delivery. The decision tree for next steps has more branches than band of monkeys family tree. Sometimes you guess.
Example; oil in the fuel. Bad injctgors is the first thing that comes to mind because it is the most common. However, the CP-3 has a seal that keeps lube and cooling fuel from leaking into the front cover. A weeping CP-3 is common in colder weather because of the componenet sparts and different expansion rates. However, it could be the seal starting to go on the shaft and leaking out a hard to see weep hole.
Example; low power and high EGT's under load mean a fuel delivery problems. Will run fine empty and no codes present but it doesn't run well. Could be the FCA sticking, COV weak, low LP delivery flow, or the pump itself is toast.
In both cases you have to start verifying th ebasics, filter, fuel flow, obvious leaks. Then the fun starts. Look for codes and with a scanner capable of seeing everything. Some DTC's will not set a CEL and not be seen by cheap readers. A fuel pressure gauge that can be tapped at the CP-3 inlet and a CTS to read parameters are a good start for basic tools.
P0148 High Pressure Common Rail (HPCR) Fueling Error Checksum
P0251 CP3 Pump Regulator Control
Two of the most common with many sources, from bad sensor to bad connection to bad battery or connections to low fuel delivery. The decision tree for next steps has more branches than band of monkeys family tree. Sometimes you guess.
