Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Deviation - Altitude Overshoot; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued Advisory / Alert; Flight Crew Returned To Clearance
Chart Or Publication; Human Factors; Aircraft
We where conducting the Localizer approach to runway 6R in CYYZ. We had started the approach at 3000 ft outside of LESOD. When we past LESOD we started down on our first step down to 1900 ft. As we started to come to 1900 ft the auto pilot went through 1900 ft about 300 ft low. My first officer disconnected the auto pilot and started to climb back up to 1900 ft. The controller came on and told us that we where getting kind of low to the ground and he asked if we where at 1900 ft on this section of the approach. I said that we where at 1900 ft as we where leveling off back at 1900 ft. We continued the approach as published and landed safely.We did our best and we caught the threat but I am going to be paying more attention to the auto pilot when we are conducting these step downs on a localizer approaches.
[The report narrative contained to additional information.]
When cleared for the ILS (glideslope out) DME Runway 06R approach at CYYZ the flight crew of a CRJ-200 failed to level at 1;900 MSL prior to SAVOS.  ATC alerted them and they returned to 1;900 feet.