Diagnostic trouble code (DTC) information

Condition 

Fig 1: Identifying Battery

Courtesy of VOLVO CARS OF NORTH AMERICA.

Diagnostic trouble code (DTC) ECM-801A is stored if the voltage from the system relay to the control module is greater than 2.5 V but lower than 3 V (signal missing) or if the power supply for the control module to the electronic throttle module is lower than 8 V (faulty signal). The fault is diagnosed when the ignition is on.

Substitute Value 

None.

Possible Source 

Signal missing 

• Faulty charging system
• Contact resistance in the terminals
• Open-circuit in the signal cable for the system relay
• Faulty system relay.

Faulty signal 

• Faulty charging system
• Contact resistance in the terminals
• Faulty system relay.

Fault symptom[s] 

• The engine fails to start
• The engine runs poorly.