MKB AAT/AEL Error Codes: Causes & Solutions (Solution)

Error codes and their causes for the AAT and AEL engines.



Error code: 281.

Speed sensor G22: Implausible signal.

Possible causes:
G22 failure.
G21 fault.
Line interruption or short circuit between terminals G22 and G21.
Signal input at the engine control unit (ECU) is defective.
Power interruption or short circuit between the control panel module and the motor (STG).


Error code: 513.

Crankshaft speed sensor G28: Implausible signal.

Possible causes:
G28 error.
Distance between the crankshaft position sensor and the toothed wheel is too large.
Metal shavings on the G28 or mounting base.

No signal.

Possible causes.
Power outage or short circuit.
G28 error.

Entrance open.

Possible causes.
Power outage or short circuit.


Error code: 519.

Manifold absolute pressure sensor G71 - implausible signal.

Possible causes:
Difference between air pressure and boost pressure at idle.

Manifold absolute pressure sensor - G71, short circuit to positive.

Possible causes:
G71 malfunction.

Short circuit to ground.
Possible causes:
G71 malfunction.

Signal too weak.

Possible causes:
Power outage or short circuit.

Signal too large.

Possible causes:
Power outage.
Boost pressure too high.

Rule difference.

Possible causes:
See error 575.


Error code: 522.

Signal too weak.

Possible causes:
Short circuit to ground.
Loose connection or corrosion caused by moisture in the connector.

Signal too large.

Possible causes:
Power interruption or short circuit after the positive terminal.

Coolant temperature sensor G62 - short circuit to ground.

Possible causes:
G62 failure.
The wire has a short circuit to ground.

Interruption/Short circuit after positive voltage.

Possible causes:
Power outage or short circuit.
G62 fault.




Error code: 523.
Intake air temperature sensor G42 - short circuit to ground.

Possible causes:
G42 error.
The wire has a short circuit to ground.

Interruption/Short circuit after positive voltage.

Possible causes:
G42 error.
Power outage or short circuit after the positive terminal.

Signal too weak.

Possible causes:
Short circuit to ground.
Loose connection or corrosion caused by moisture in the connector.

Signal too large.

Possible causes:
G42 error.



Error code: 526.

Brake light switch, implausible signal.

Possible causes:
Switch set incorrectly.
The F and F47 connections are reversed.
Power outage.
F or F47 defective.
Fuse blown.
Both brake lights are defective.



Error code: 532.

Supply voltage signal too low.

Possible causes:
The control unit was connected with the ignition switched on.
Battery condition: poor.
Defective surge protection relay J249 or fuel injection relay J322.
Power outage or short circuit.



Error code: 539.


Signal too weak.

Possible causes:
Fuel is getting too hot.
G81 error.

Signal too large.

Possible causes:
Power interruption or short circuit after the positive terminal.

Fuel temperature sensor G81, short circuit to ground.

Possible causes:
The wire has a short circuit to ground.
Fuel preheating system malfunction or check valve failure between...
The filter and tank were installed in the wrong direction in the return line.

Interruption/Short circuit after positive voltage.

Possible causes:
G81 failure.
7-pin connector for the fuel injection pump is disconnected.



Error code: 541.

Potentiometer for slider travel, G99 signal too low.

Possible causes:
Line interruption or short circuit to ground.
G99 malfunction.

Signal too large.

Possible causes:
Power interruption or short circuit after the positive terminal.
G99 malfunction.
7-pin connector for the fuel injection pump is disconnected.

Implausible signal.

Possible causes:
Quantity setting device misadjusted.
Needle feed mechanism G80 defective.



Error code: 542.
Needle feed motor G80: Overvoltage/short circuit after positive voltage.
Input open, short circuit to ground.

Possible causes:
G80 failure.
Power outage or short circuit.

Implausible signal.

Possible causes:
Fuel shortage.
Air in the fuel system.
Filter or inlet pipe clogged.
G28 encoder disc is bent or loose.
Fuel injection pump failure.
G80 error.
Signal input at the engine control unit (ECU) is defective.



Error code: 550.
Injection start control, pressure difference.

Possible causes:
Power outage.
Fuel injection start valve (N108) defective.
Fuel tank emptied.
Fuel supply not working correctly.
Fuel shortage.
Air in the fuel system.
Funding start not OK.
Injection pump stroke blocked.


Error code: 552.

Potentiometer for mass airflow sensor G19, implausible signal.

Possible causes:
G19 malfunction.
Brake pedal monitoring implausible.
Vacuum hose of the EGR valve is faulty, or the EGR valve is constantly open.

Signal too weak.

Possible causes:
G19 malfunction.
Power outage or short circuit.

Signal too large.

Possible causes:
Power interruption or short circuit after the positive terminal.



Error code: 560.
Exhaust gas recirculation control difference.

Possible causes:
Exhaust gas recirculation (EGR) valve defective.
Hoses swapped, not connected, clogged, or leaking.
ECU (Engine Control Unit) defective (only applies to part number: 4A0 907 401 with software version D24).


Error code: 575.
Intake manifold pressure, control differential.

Possible causes:
Hoses connected incorrectly, not properly attached, leaking.
Boost pressure too high.
Hose connected to G71 is faulty.



Error code: 625.
Speed signal: implausible signal.

Possible causes:
No signal from the sender for the speedometer (G21 or G22).
G21 or G22 is defective.
Power outage.



Error code: 668.

Board voltage, terminal 30, signal too low.

Possible causes:
Battery charge level is low.
Relay J322 is stuck.
Power outage.


Error code: 671.

Switch for GRA E45, undefined switch state.

Possible causes:
E45 fault.
Power outage or short circuit.



Error code: 741.

Brake pedal monitoring: implausible signal.

Possible causes:
Brake light switch (F) defective.
Brake pedal switch (F47) defective.
Switch set incorrectly.
Power outage.
Fuse blown.
Both brake lights are defective.
Plugs swapped.



Error code: 765.
Sensor for control slide travel G149.

Possible causes:
G149 error.
Power outage or short circuit.
7-pin connector for ESP, disconnected.

Implausible signal.

Possible causes:
Quantity setting device misadjusted.
G80 error, usually with error code 542.



Error code: 777.
Accelerator pedal position sensor G79: Implausible signal.

Possible causes.
G79 malfunction.
G79: Line interruption or short circuit.

Signal too large.

Possible causes.
G79 malfunction.
Power outage.

Signal too weak.

Possible causes.
Power outage or short circuit.



Error code: 819
Error source 0333.

Possible causes:
J322 malfunction.
Short circuit.



Error code: 1054
Relay for power supply, class 30, model J317.

Possible causes:
J322 malfunction.
Short circuit.



Error code: 1117
Load signal for generator terminal DF: implausible signal.

Possible causes:
Generator failure.
Voltage regulator faulty.
Power outage or short circuit.



Error code: 1237
Fuel shut-off valve N109, mechanical fault.

Possible causes:
N109 is leaking, defective, or stuck.

Implausible signal.

Possible causes: Cable interruption or short circuit to ground.
N109 is defective.

Interruption or short circuit, connect to ground.

Possible causes: Cable interruption or short circuit to ground.
N109 is defective.



Error code: 1242
Power amplifier in the control unit: implausible signal, interruption or short circuit to positive.

Possible causes:
Fuel injection timing valve N108 is defective.
N75 defective.
N18 fault.
Glow plug relay J52 is defective.
Short circuit after the positive terminal in the wiring to the preheating indicator lamp (K29).



Error code: 1268
Set Point N146, Control Difference.

Possible causes:
Power outage or short circuit.


Implausible signal.

Possible causes:
Quantity setting device misadjusted.
Der turnout is blocked due to dirt.
Implausible signal from G99 or G149.



Error code: 17978.
Engine control unit locked.

Possible causes:
Unauthorized start attempt.
Key.
Manipulation attempt.
Short circuit.
Communication line.
incorrect encoding.
Error in the system.
Drive-away protection.
Immobilizer control unit.
defective/missing
Engine control unit replaced, but not programmed.
"Drive-away protection adjusted."



Error code: 65535
Engine control unit (ECU) failure.