6.0L Power Stroke Diagnostic Information & Procedures

Note - see links at bottom of page for various related step-by-step 6.0L Power Stroke repair procedures.

Smoke Signals - White, Black, & Blue Smoke Indications

The color of any visible smoke emitted from the tailpipe is a useful indicator in combustion characteristics (or lack thereof). Identifying smoke is particularly useful in hard start, no start, and performance related issues. A lack of smoke is equally beneficial in no start/hard start scenarios.

White smoke - White smoke is the result of raw, atomized fuel leaving the combustion chamber. Raw fuel is indicative that there is a lack of heat in the combustion chamber and therefore auto-ignition is not occurring. Recall that diesel fuel is ignited by the heat produced from compression. However, glow plugs serve as a starting aid to produce the heat necessary to begin the combustion process when an engine is cold. White smoke during cranking often points to a glow plug system issue; the engine is receiving fuel, but it is not igniting. White smoke while running may indicate a cylinder with low compression or, in certain circumstances, an injector that is stuck open. Note - "white" smoke may also be described as lightly gray in color.

Gray smoke - Gray smoke is the result of oil burning in the exhaust system. This is often caused by a turbocharger seal failure on the turbine (exhaust) side, causing engine oil to enter the exhaust system and burn. Under such circumstances, engine oil may drop from the tailpipe; this almost always indicates that a turbocharger replacement/overhaul is necessary.

Black smoke - Black smoke is the result of partially burnt fuel; there is adequate heat for combustion, however the mixture is rich and thus there is a lack of air or abundance of fuel during combustion. If black smoke is present and a low power condition is being experienced, an airflow issue is suspect (low turbocharger boost, intercooler boot leak, plugged air filter, etc).

Blue smoke - Blue smoke indicates that engine oil is being burned in the combustion chamber. The smoke resembles that emitted by a 2 stroke gasoline engine that is running rich. This typically indicates that there is a leak on the compressor side of the turbocharger via a failed seal.

Diagnostic Trouble Codes (DTCs) & Harness Chaffing

DTCs are your greatest asset and worse enemy when it comes to 6.0L Power Stroke diagnostics. In many situations, a DTC may indicate a system that is malfunctioning while the individual sensor that it refers to is not the problem. An injector control pressure low DTC, for example does not necessary mean that the ICP sensor is malfunctioning; although it might be. Another example is the occurrence of P2614 (camshaft position sensor) and P2617 (crankshaft position sensor) being set simultaneously. This is never an issue with the two sensors and almost always set as the result of a long crank, no start condition. The moral of the story is that a comprehensive diagnosis is always required until the underlying problem is identified and verified.

Harness chaffing is historically a serious concern on 6.0L Power Stroke engines. This is a common issue that surfaced shortly after the engine's release. Don't assume that this doesn't affect you - always perform a quick survey of your wiring harness and look for portions of wire loom that are chaffed or wires that are exposed. In extreme circumstances, wires can chaff inside the wire loom while the wire loom remains intact. If you're chasing electrical demons, this should be you're starting point.

A scantool or diagnostic software with enhanced diagnostic features is ideal when troubleshooting 6.0L Power Stroke engine problems. You need to be able to perform basic and advanced system tests in addition to monitoring the output of various sensors simultaneously. In the information below when we refer to "monitoring" a PID, we're doing so with AutoEnginuity's diagnostic software suite.

Notes about commonly misleading DTCs:

6.0L Power Stroke No Start, HARD START, RUNS ROUGH, and/or Stalls

WARNING! - NEVER USE STARTING FLUID TO START A DIESEL ENGINE REGARDLESS OF PRODUCT CLAIMS. SEVERE ENGINE DAMAGE MAY OCCUR.

Check engine oil level - The 6.0L Power Stroke relies on a high pressure oil circuit to build fuel pressure. An engine will stall and a no start condition may occur if the engine oil level is low as it starves the high pressure system. No oil pressure = no injection pressure.

Verify battery condition - Low battery voltage can cause a slow crank condition and/or may contribute to FICM failure. Approximately 180 - 200 rpm cranking speed is required to start an engine. Battery voltage should measure 12.5 - 12.7 volts for a fully charged battery in good condition. If battery voltage is within this range but engine cranks slowly or intermittently, suspect corroded/loose connections and/or faulty starter.

Test for proper glow plug operation - A GPCM (glow plug control module) fault will typically set a DTC, a glow plug or glow plug wiring issue will not always set a DTC. Individual glow plug condition can be tested by measuring the resistance between each individual glow plug circuit at the GPCM and the negative battery cable. If white smoke is present while cranking, a glow plug system issue is likely (fuel is being injected into the cylinders accordingly but there is a lack of heat necessary for combustion to occur). If no smoke is present while cranking, the glow plug system is unlikely the cause of a no start/hard start condition.

Glow plug cycle time is determined by engine oil temperature (EOT) and barometric pressure. If the glow plugs do not cycle, verify the readings of these sensors (barometric pressure is equal to atmospheric pressure, EOT should read close to ambient temperature when engine is cold).

Verify ICP & IPR valve function - A minimum 500 psi injector control pressure is necessary to start the 6.0L Power Stroke diesel. If oil pressure does not reach or drops below 500 psi an injector will not fire. ICP typically reaches anywhere between 800 and 2,000 psi while cranking. If ICP sensor reading is low, erratic, rises slowly while cranking, or there is another reason to suspect it is bad unplug the sensor and attempt to start the engine (ICP defaults to 750 psi when sensor is unplugged). If engine starts, ICP sensor must be replaced.

The IPR duty cycle relates to the position of the IPR valve. At 15% duty cycle, the IPR valve is fully open. At 85% duty cycle, the IPR valve is fully closed. In the closed position oil pressure is increased and in the open position oil pressure is reduced (HPOP pressure bled off into the crankcase). Monitor ICP actual, ICP desired, and IPR valve duty cycle simultaneously. While cranking engine, IPR duty cycle should start at approximately 85% and slowly decrease during a long crank condition once ICP climbs. An IPR valve defaults to 15% if it is unplugged or has failed. In this instance, an engine will not start as it will not be able to build oil pressure; a low ICP condition should be present. IPR valve duty cycle should not exceed 30% at idle once the engine reaches operating temperature. If it does, suspect a leak in the high pressure oil circuit.

ICP actual will tend to trail ICP desired (what the PCM is commanding) while cranking, but the two should generally be close. If ICP desired is significantly higher than ICP actual the IPR valve may not be functioning correctly and is allowing oil pressure in the high pressure circuit to bleed off. A high pressure system leak (failed o-ring, for example) or bad high pressure oil pump (HPOP) can also cause a low ICP condition. Always verify IPR function before assuming high pressure oil system leak or HPOP failure. A high pressure oil system bleed down test is typically necessary to locate leaks. The test requires a special fitting that allows the system to be pressurized with air while the IPR valve is remotely commanded closed; leaks are then audibly traced.

Verify FICM voltage - 45 to 48 volts is acceptable. Anything lower than 45 and the FICM needs to be replaced. If FICM output voltage is 0, check FICM vehicle power relay (#304, labeled IDM relay in owners manual). Replace FICM relay when replacing FICM regardless of condition. Note - engine may still run if FICM voltage is lower than 45v, but this signifies a failure is highly likely in the near future.

Verify FICM sync - FICM sync should read a "1" bit (1 for yes, 0 for no) while engine is being cranked or running. A "yes" or "1" value for FICM sync indicates that the FICM is receiving CPS/CKP signal from the PCM. If FICM sync returns a "0" or "no" value, CPS/CKP signal is not being transmitted to the FICM. Verify sensor conditions, connectors, and all wiring to the PCM and FICM.

Verify CPS, CKP sensor - If a camshaft or crankshaft position sensor loses signal a DTC will be set. A P2614 and P2617 DTC may be set simultaneously during a long crank condition when there is in fact no problem with either signal. CKP sensor failures are rare. CPS failures are more common. The odds that both sensors will fail together is slim-to-none.

Verify fuel pressure - A port on the fuel filter housing is used to measure fuel pressure. A schrader valve fitting is required to adapt most common fuel pressure gages to the port. 45 psi minimum should be observed KOEO, while cranking, and KOER. Any reading below 45 psi indicates a plugged fuel filter, fuel system leak, or faulty lift pump.

Verify fuel quality, drain fuel-water separator - Drain the frame mounted fuel-water separator and check for excessive water in the fuel. Cycle key to the "run" position several times, then drain and check again. If water continues to fill the separator, the fuel tank may need to be drained. Running an engine with excessive water in the fuel may damage injectors.

Perform an injector buzz test - An injector "buzz" or "click" test is performed to identify a bad injector or injectors by means of an audible test. When an injector buzz test is initiated the engine will sequentially activate each individual injector solenoid, producing buzzing and clicking sounds as the solenoids are energized. All injectors should produce the same characteristic buzz/clicking sound; any injector that sounds different from the rest should be inspected and may require replacement. If no injectors buzz once the test is initiated, retest the FICM.

Perform a cylinder contribution test - A cylinder contribution or power balance test determines how each individual injector contributes to engine rpm following an injection event. A weak injector will not contribute as much as a strong injector and thus engine rpm will decrease after that injector is fired. The FICM automatically adjusts injector pulse width to account for variances between injection event strength. This function must be briefly turned off in order to perform this test. This is achieved by selecting an injector as if you were to turn it off manually via your scantool/diagnostic system. Select any injector, but do not disable it; this will give you roughly 1 minute to initiate the power balance test before the automatic pulse width adjustment function returns. A straight line is desirable in the results of the cylinder contribution test. If rpm drops significantly for one or more injectors, they should be replaced.

Hard start, stalling only when engine is cold - Suspect high pressure oil system leak. A leak in the high pressure oil system may allow oil to drain out of the system while the engine sits. Monitor ICP; if ICP is low but finally reaches a normal state after excessive cranking and/or following a series of stall events, the HPOP may be starving for oil until the reservoir is refilled. Perform aforementioned ICP, IPR monitoring tests while engine is running to verify that the system functions within spec once engine is able to warm up.

Engine only stalls/will not start when hot - Check FICM voltage with engine at operating temperature. Suspect high pressure oil leak at STC (snap-to-connect) fitting on high pressure oil pump; extremely common.

Powertrain control module (PCM) - There is not a suitable nor standardized test for a PCM unless it is completely blank. All other systems should be tested thoroughly before assuming that a PCM is suspect. PCM failures do happen, but are less common than the aforementioned possibilities. The failure rate is much higher on engines with aftermarket tuners/programmers. Thoroughly inspect wiring harness for chaffing before suspecting PCM. If a no start condition occurs immediately following aftermarket tunes being uploaded, the PCM is likely the problem.

Low Power, Performance, & Driveability Concerns

Over-boost condition - A clogged EGR valve where the valve becomes stuck in the closed position can cause an over-boost condition (excessive MAP). Sticking vanes/unison ring in the turbine housing of the turbocharger can also cause an over-boost condition. If MAP is high under light load conditions, VGT vanes are sticking/stuck.

Low power condition, excessive turbocharger lag and/or low turbocharger boost - A number of PIDs need to be monitored in order to identify low power and poor turbocharger performance conditions. Causes include a stuck unison ring in the turbine housing, faulty VGT solenoid, exhaust leak, intake leak (pressure side of turbo), faulty EBP sensor, or faulty MAP sensor. The MAP and EBP sensors can be checked with KOEO. They should both read ~ 14.7 psi at sea level.

Excessive or insufficient EGR flow, low power condition - An EGR valve stuck in the open position can cause a low performance condition. If an EGR DTC is present, the first step is to remove, clean, and reinstall the EGR valve with new gaskets. You can also test the EGR position range by manually commanding it open and close; you will hear the idle sound change when the valve position changes.

Engine jerking, cutting in and out, low power - Fuel pressure, oil pressure, and injector condition can cause such symptoms. Start by testing fuel pressure under load, followed by verifying ICP/IPR function. If these systems are operating within spec, run an injector buzz test.

Clogged oil cooler - The pressure differential between EOT and ECT should not exceed 10 degrees F once the engine has reached operating temperature. If the temperature difference exceeds this by a wide margin, the oil cooler is likely clogged. Coolant blowing out of the degas bottle is a sign that the oil cooler has failed.

Identifying a failed EGR cooler - Loss of engine coolant is the most prominent sign that an EGR cooler has failed. In extreme cases, steam will be emitted out of the tailpipe. A simple way to check the EGR cooler condition is to pull the EGR valve. If there is any white residue or white "crystals" stuck to the EGR valve, the cooler is leaking and needs to be replaced.

6.0L Power Stroke Diagnostic Parameter Specs & Ranges

Common Ford Part Numbers

See 6.0L Power Stroke Maintenance Schedule, Fluid Capacities Service Information for part numbers related to engine maintenance procedures.