Section 16.1
Mechanical Troubleshooting
The tables that follow are designed to identify the causes of common problems, suggest further checks and appropriate remedies. When dealer service is necessary, this is mentioned in the table.
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Problem - The Engine Will Not Crank |
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Cause |
Remedy |
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The batteries are damaged or weak. |
Test the batteries. Replace them, if needed. |
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The ignition switch is damaged. |
Replace the ignition switch. |
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The battery cables are damaged and/or corroded. |
Clean or replace the battery cables. |
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The starter is damaged and/or worn. |
Have an authorized dealer replace the starter. |
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The clutch or transmission is damaged. |
Bring the vehicle to an authorized dealer for service. |
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There is internal damage to the engine. |
Bring the vehicle to an authorized dealer for service. |
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Problem—The Engine Turns Over Slowly |
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Cause |
Remedy |
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The batteries are damaged or weak. |
Test the batteries. Replace them, if needed. |
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The ignition switch is damaged. |
Replace the ignition switch. |
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The battery cables are damaged and/or corroded |
Clean or replace the battery cables. |
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The starter is damaged and/or worn. |
Have an authorized dealer replace the starter. |
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The engine oil does not meet the correct specifications. |
Change the engine oil, using the correct type of oil. |
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The transmission fluid does not meet the correct specifications. |
Change the transmission fluid, using the correct type of fluid. |
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Problem—The Engine Cranks, But Won't Start |
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Cause |
Remedy |
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The batteries are damaged or weak. |
Test the batteries. Replace them, if needed. |
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The cranking speed is not set correctly. |
Bring the vehicle to an authorized dealer for service. |
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No intake air preheater is installed, and it is too cold to start without one. |
Install an intake air preheater. |
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The intake air preheater is malfunctioning. |
Check the intake air preheater, and replace it, if necessary. |
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The camshaft TDC sensor and/or the crank angle position sensor are out of adjustment. |
Push both sensors into their holes as far as they will go. If this does not solve the problem, bring the vehicle to an authorized dealer for service. |
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The camshaft TDC sensor and/or the crank angle position sensor are damaged. |
Bring the vehicle to an authorized dealer for service. |
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There is air in the fuel system. |
Check the fuel lines for air pockets. Prime the fuel system and start the engine. |
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The air filter is clogged. |
Clean or replace the air filter. |
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The fuel filter is clogged. |
Replace the filter element. |
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The exhaust brake valve is malfunctioning. |
Have an authorized dealer check the operation of the valve. |
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The valves are not adjusted properly. |
Check the valve lash. |
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There are other problems in the fuel system. |
Bring the vehicle to an authorized dealer for service. |
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Problem—The Engine Starts Only After Cranking for a Long Time |
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Cause |
Remedy |
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The fuel tank is low or empty. |
Add fuel and prime the fuel system, if necessary. |
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There are leaks in the fuel lines. |
Check the fuel lines for leaks and repair them, if necessary. |
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The fuel filter is clogged. |
Replace the filter element. |
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The fuel line, the fuel pre-filter, or the screen in the fuel tank is blocked. |
Clean and prime the system. Have the fuel lines and filters checked by an authorized dealer. |
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The camshaft TDC sensor and/or the crank angle position sensor are out of adjustment. |
Push both sensors into their holes as far as they will go. If this does not solve the problem, bring the vehicle to an authorized dealer for service. |
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The camshaft TDC sensor and/or the crank angle position sensor are damaged. |
Bring the vehicle to an authorized dealer for service. |
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There are other problems in the fuel system. |
Bring the vehicle to an authorized dealer for service. |
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Problem—The Engine Starts, But Dies |
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Cause |
Remedy |
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The fuel tank is low or empty. |
Add fuel and prime the fuel system, if necessary. |
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The fuel filter is clogged. |
Replace the filter element. |
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The fuel line, the fuel pre-filter, or the screen in the fuel tank is blocked. |
Clean and prime the system. Have the fuel lines and filters checked by an authorized dealer. |
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The camshaft TDC sensor and/or the crank angle position sensor are out of adjustment. |
Push both sensors into their holes as far as they will go. If this does not solve the problem, bring the vehicle to an authorized dealer for service. |
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The camshaft TDC sensor and/or the crank angle position sensor are damaged. |
Bring the vehicle to an authorized dealer for service. |
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The constant-throttle valves are malfunctioning. |
Bring the vehicle to an authorized dealer for service. |
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There are other problems in the fuel system. |
Bring the vehicle to an authorized dealer for service. |
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Problem—The Engine Fan Doesn't Work |
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Cause |
Remedy |
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The fan hub is damaged. |
Replace the fan hub. |
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The fan wiring is damaged. |
Repair the fan wiring. |
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The parameter settings in the PLD or VCU control unit are incorrect. |
Have an authorized dealer reprogram the control unit. |
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Problem—The Engine Fan Is Constantly On |
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Cause |
Remedy |
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The fan override switch is on. |
Check the operation of the fan override switch. |
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The fan hub is damaged. |
Replace the fan hub. |
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The parameter settings in the PLD or VCU control unit are incorrect. |
Have an authorized dealer reprogram the control unit. |
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Problem—Fuel Consumption Is Too High |
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Cause |
Remedy |
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The tires are not properly inflated. |
Check all tires for correct pressure. |
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The air filter and/or intake air system is clogged. |
Check the air restriction indicator. Clean the intake air system and replace the air filter if necessary. |
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The fuel filter is clogged. |
Replace the filter element. |
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The exhaust brake valve is malfunctioning. |
Have an authorized dealer check the operation of the valve. |
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The engine performs poorly, or does not develop full power. |
The remedies are listed in "The Engine Performs Poorly, Does Not Develop Full Power." |
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Problem—The Engine Performs Poorly, Does Not Develop Full Power |
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Cause |
Remedy |
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The air filter and/or intake air system is clogged. |
Check the air restriction indicator. Clean the intake air system and replace the air filter if necessary. |
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The exhaust brake valve is malfunctioning. |
Have an authorized dealer check the operation of the valve. |
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The fuel filter is clogged. |
Replace the filter element. |
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There are other problems with the fuel system. |
Bring the vehicle to an authorized dealer for service. |
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The valves are not adjusted properly |
Check the valve lash. See |
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The coolant temperature sensor is damaged or reading incorrectly. |
Bring the vehicle to an authorized dealer for service. |
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The fuel temperature sensor is damaged or reading incorrectly. |
Bring the vehicle to an authorized dealer for service. |
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The engine oil temperature sensor is damaged or reading incorrectly. |
Bring the vehicle to an authorized dealer for service. |
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The charge-air temperature sensor is damaged or reading incorrectly. |
Bring the vehicle to an authorized dealer for service. |
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There are problems with the PLD or VCU control unit. |
Bring the vehicle to an authorized dealer for service. |
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There is internal damage to the engine. |
Bring the vehicle to an authorized dealer for service. |
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Problem—The Engine Is in Emergency Running Mode (constant speed 1,300 rpm) |
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Cause |
Remedy |
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The PLD or VCU control unit is damaged. |
Bring the vehicle to an authorized dealer for service. |
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Problem—The Coolant Temperature Is Above Normal |
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Cause |
Remedy |
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The coolant level is too low. |
Check for coolant leaks, and repair as needed. |
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The poly-V belt is loose. |
Tighten or replace the poly-V belt. |
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The coolant temperature gauge and/or sensor is not reading correctly. |
Bring the vehicle to an authorized dealer for service. |
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The radiator is damaged or dirty. |
Clean the radiator. Repair or replace the radiator if necessary. |
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The coolant pump is damaged. |
Have an authorized dealer replace the coolant pump. |
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The thermostat is damaged. |
Have an authorized dealer replace the thermostat . |
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The fan is not operating properly. |
Bring the vehicle to an authorized dealer and have the fan hub checked. Bring the vehicle to an authorized dealer and have the parameter settings reprogrammed in the engine control unit (PLD) or vehicle control unit (VCU). |
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Problem—The Coolant Temperature Is Below Normal |
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Cause |
Remedy |
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The coolant temperature gauge and/or sensor is not reading correctly. |
Bring the vehicle to an authorized dealer for service. |
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The thermostat is damaged. |
Have an authorized dealer replace the thermostat. |
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The fan is not operating properly. |
Bring the vehicle to an authorized dealer and have the fan hub checked. Bring the vehicle to an authorized dealer and have the parameter settings reprogrammed in the engine control unit (PLD) or vehicle control unit (VCU). |
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Problem—The Cooling System Is Losing Coolant |
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Cause |
Remedy |
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There is an external coolant leak. |
Repair the leaking component. |
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The radiator cap is leaking. |
Replace the radiator cap. |
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The air compressor head is damaged. |
Have an authorized dealer replace the air compressor. |
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The cylinder head gasket is leaking. |
Have an authorized dealer replace the head gasket. |
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Problem—There Is Coolant in the Engine Oil |
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Cause |
Remedy |
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The cylinder head gasket is damaged. |
Have an authorized dealer replace the head gasket. |
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The oil/water heat exchanger is leaking. |
Have an authorized dealer replace the heat exchanger. |
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There is an internal coolant leak. |
Bring the vehicle to an authorized dealer for service. |
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Problem—There Is Foam in the Engine Oil |
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Cause |
Remedy |
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The oil level is too low or too high. |
Correct the oil level. |
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The oil has not been changed within the recommended interval. |
Change the oil. |
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The oil is not of the recommended quality. |
Change the oil. |
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Problem—The Engine Oil Pressure Is Low |
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Cause |
Remedy |
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The oil pressure gauge and/or sensor is not reading correctly. |
Bring the vehicle to an authorized dealer for service. |
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There is fuel in the oil. |
Bring the vehicle to an authorized dealer for service. |
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The oil filter is clogged. |
Replace the filter element. |
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The oil filter bypass valve is damaged. |
Replace the bypass valve. |
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The oil pump and/or relief valve is damaged. |
Have an authorized dealer replace the oil pump and/or relief valve. |
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Problem—The Engine Exhaust Is White |
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Cause |
Remedy |
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The fuel is of poor quality. |
Add fuel of the right quality. |
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The intake air preheater is malfunctioning. |
Check the intake air preheater, and replace it, if necessary. |
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The valves are not adjusted properly. |
Check the valve lash. |
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Problem—The Engine Exhaust Is Black |
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Cause |
Remedy |
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The air filter and/or intake air system is clogged. |
Check the air restriction indicator. Clean the intake air system and replace the air filter if necessary. |
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The exhaust brake valve is malfunctioning. |
Have an authorized dealer check the operation of the exhaust brake valve. |
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The intake air preheater is malfunctioning. |
Check that the heater is not staying on all of the time. |
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The valves are not adjusted properly. |
Check the valve lash. |
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There is damage to the fuel system: the fuel pump, one or more fuel injectors, or one or more unit pumps are damaged. |
Bring the vehicle to an authorized dealer for service. |
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The charge-air temperature sensor is damaged. |
Bring the vehicle to an authorized dealer for service. |
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There is internal damage to the engine. |
Bring the vehicle to an authorized dealer for service. |
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Problem—The Engine Exhaust Is Blue |
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Cause |
Remedy |
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The engine oil level is too high (engine oil is reaching the combustion chamber). |
Adjust the oil level, and then have the oil level checked by an authorized dealer. |
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The turbocharger is leaking oil. |
Have an authorized dealer replace the turbocharger |
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The valve stem seals are loose or damaged. |
Have an authorized dealer replace the seals. |
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The piston rings are worn. |
Have an authorized dealer replace the piston rings. |
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Problem—Engine Brake Performance Is Poor |
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Cause |
Remedy |
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The engine brake control switch is damaged. |
Replace the switch. |
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The exhaust brake valve is not operating properly. |
Have an authorized dealer check the operation of the exhaust brake valve. |
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The constant-throttle valves are malfunctioning. |
Bring the vehicle to an authorized dealer for service. |
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Components of the PLD and/or VCU control unit are damaged. |
Bring the vehicle to an authorized dealer for service. |
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Problem—Cruise Control Is Not Working |
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Cause |
Remedy |
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One or more of the cruise control switches are damaged. |
Replace the damaged switch. |
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Components of the PLD and/or VCU control unit are damaged or not working properly. |
Bring the vehicle to an authorized dealer for service. |
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Problem—The Battery Charge Indicator Light Does Not Come On When the Engine Is Not Running |
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Cause |
Remedy |
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The bulb is damaged. |
Change the bulb. |
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The circuit is broken. |
Repair the break in the circuit. |
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Problem—The Battery Charge Indicator Light Comes On When the Engine is Running |
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Cause |
Remedy |
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The poly-V belt is too loose. |
Check the belt tension; if necessary, have an authorized dealer replace the belt tensioner. |
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The belt tensioner is damaged. |
Have an authorized dealer replace the belt tensioner. |
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The poly-V belt is worn or damaged. |
Replace the belt. |
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The alternator is damaged (has a damaged rectifier or voltage regulator). |
Have an authorized dealer replace the alternator. |
| MBE 4000 Service Manual - 6SE412 |
| Generated on 10-13-2008 |