Turbo Speed Sensor - AEC-TBR-301, 401, 402, 403, 404, 411, 412, 413 and 414

Common issues

• Sensor gap (air gap to the toothed wheel) drifting out of tolerance, causing erratic or lost speed signal
• Cable or connector damage from heat and vibration in the turbocharger/exhaust area
• Sensor tip contamination or damage from oil mist or debris
• Internal coil failure after prolonged high-temperature exposure, giving total signal loss
• Loose sensor mounting allowing vibration-induced signal noise
• Incorrect sensor gap set after turbocharger overhaul, giving a false low or fluctuating rpm reading

Inspection checklist

• Check sensor mounting is tight and the gap to the toothed/gear wheel is within the maker's specified range
• Inspect sensor cable and connector for chafing, heat damage, or moisture ingress
• Compare indicated turbocharger speed against an independent handheld tachometer reading where accessible
• Check for erratic, dropped, or noisy speed signal at the alarm/monitoring system
• Inspect the sensor tip for physical damage or contamination after removal
• Confirm overspeed alarm and slow-down setpoints match the engine builder's requirements

Service intervals

Critical spares

• Turbo speed sensor (correct model/range for the application)
• Sensor cable/connector kit
• Mounting bracket and gap-setting shims if used

Safety

• Turbocharger overspeed protection depends on a working, correctly gapped speed sensor - do not run the engine with a known-faulty sensor and a disabled overspeed trip
• Sensor removal/installation on a running or recently stopped hot turbocharger risks burns - isolate and allow cooling first
• Fit only a sensor matching the correct type and range for the application - a mismatched sensor can give a false reading and mask a real overspeed condition

Class survey

Note: catalogued under 'Radar Level Gauge' / 'Cargo Level & Temperature Gauging' - this is a turbocharger speed sensor, an engine monitoring component, not a level gauge; content above addresses the actual product. Turbocharger overspeed protection and its sensor are typically checked as part of main/auxiliary engine safety system testing at survey.