Selective Catalytic Reduction (SCR) System

Selective Catalytic Reduction (SCR) System (Some Models)

The SCR system is designed to reduce nitrogen oxide (NOx) in the exhaust gas and purify the exhaust gas by injecting it with Diesel Exhaust Fluid (DEF).

Be careful not to allow the DEF to run out. If the DEF completely runs out, the SCR system will not operate normally.

When the remaining DEF is low, a message is displayed on the multi-information display, and the SCR warning light turns on/flashes.

Refer to Selective Catalytic Reduction (SCR) System Indications (Search).

In this case, consult an Authorized Mazda Dealer. If DEF needs to be replenished, add DEF following the specified procedure.

Refer to Diesel Exhaust Fluid (DEF) Replenishment (Search).

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DEF needs to be replenished periodically according to the scheduled maintenance information.
Normally, the vehicle can be driven about 12,000 km (7,500 miles) before the DEF needs to be replenished. However, it may need to be replenished earlier depending on the driving and environmental conditions (such as putting a high load on the engine while driving or driving the vehicle at high altitudes).
The sound of the SCR system operating may be heard from the area under the vehicle, however, this does not indicate a problem.

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Selective Catalytic Reduction (SCR) System Indications

As the remaining amount of Diesel Exhaust Fluid (DEF) lowers, the SCR system notifies the driver using the following indications.

The vehicle speed may be restricted for a while even if the warning light turns off after replenishing the DEF. To cancel the vehicle speed restriction immediately, switch the ignition OFF after the warning light turns off and then switch the ignition ON again.

Status	Warning sound	SCR warning light	Driving restriction
Remaining DEF has decreased (Maximum driving distance : 966 km (600 miles) or less)	Sound is activated when ignition is switched ON	Turns off	None
Remaining DEF is low (Maximum driving distance : 644 km (400 miles) or less)	Sound is activated when ignition is switched ON	Turns on	Vehicle speed of 80 km/h (50 mph) or slower
Remaining DEF is extremely low (Maximum driving distance : 322 km (200 miles) or less)	Sound is activated when ignition is switched ON	Flashes	Vehicle speed of 48 km/h (30 mph) or slower
No remaining DEF (Maximum driving distance : 0 km (0 miles))	Sound is activated when remaining-distance-to-empty indication is 0 km (0 miles)	Flashes	Creep travel^*1

The vehicle speed will be restricted (Creep travel) the next time the vehicle is driven after the maximum driving distance reaches 0 km (0 miles).

The following indications are displayed when there is a problem with the SCR system/DEF. If there is a problem with the SCR system/DEF, consult an Authorized Mazda Dealer.

The vehicle speed may be restricted for a while even if the warning light turned off after having the vehicle repaired. To cancel the vehicle speed restriction immediately, switch the ignition OFF after the warning light turns off, and then switch the ignition ON again.

Status	Warning sound	SCR warning light	Driving restriction
There is a problem with the SCR system/DEF (Maximum driving distance : 402 km (250 miles) or less)	Sound is activated when there is a problem Sound is activated when ignition is switched ON	Flashes	None
Condition in which a problem with SCR system/DEF continues (Maximum driving distance : 201 km (125 miles) or less)	Sound is activated when ignition is switched ON	Flashes	Vehicle speed of 48 km/h (30 mph) or slower
Condition in which a problem with SCR system/DEF continues (Maximum driving distance : 0 km (0 miles))	Sound is activated when remaining-distance-to-empty indication is 0 km (0 miles)	Flashes	Creep travel^*1
DEF has been replenished over the specified amount	―	Turns on	None

The vehicle speed will be restricted (Creep travel) the next time the vehicle is driven after the maximum driving distance reaches 0 km (0 miles).