Technician Chat Features
Technician Chat gives you instant answers to mechanical reference questions — torque specs, sensor locations, fluid capacities, fault code meanings, and more. Available to paid subscribers.
What Technician Chat Can Do
- Torque specifications — fastener torques, sequences, stage torques
- Sensor and component locations — where components are physically located
- Fluid capacities — engine oil, coolant, DEF, transmission, axle
- Firing orders — cylinder firing sequences for any engine
- DEF specifications — quality, concentration, storage, system specs
- Fault code meanings — SPN/FMI definitions, P-codes, U-codes
- Component descriptions — what a component is and how it works
- System explanations — EGR, DPF, SCR, DEF, fuel, cooling, and more
- Belt and chain routing — serpentine belt routing, timing chain info
Example Questions & Answers
Q:What's the torque spec for a DD15 injector hold-down?
A:37 ft-lbs (50 Nm) — two-stage: 18 ft-lbs first pass, 37 ft-lbs final. Always use new hold-down bolts.
Q:Where is the NOx sensor on a PACCAR MX-13?
A:Upstream NOx sensor is on the passenger side exhaust, between the DPF outlet and SCR inlet. Downstream is in the tailpipe after the SCR.
Q:What does SPN 3251 FMI 0 mean?
A:SCR Catalyst Efficiency — data valid but above normal range. The SCR is not converting NOx at the expected rate. Common causes: contaminated DEF, failed DEF injector, degraded SCR catalyst.
Q:What's the coolant capacity for a Cummins ISX15?
A:Approximately 52 quarts (49 liters) total system. Always use Cummins-approved coolant — do not mix types.
Q:What's the firing order for a Detroit DD15?
A:DD15 firing order: 1-5-3-6-2-4. Six-cylinder inline engine.
How to Use It
- 1
Sign in to your account
Technician Chat is included with all paid AI Diesel Tech plans.
- 2
Navigate to Technician Chat
Find Technician Chat in the main navigation or go directly to /technician-chat.
- 3
Ask your question
Type your question in plain language. Be specific — include the engine model and year for the most accurate answer.
- 4
Get your answer instantly
Technician Chat responds in seconds with the specific value or information you need.
- 5
Ask follow-up questions
The chat maintains context across the conversation. Ask follow-up questions without repeating the engine model.
Try Technician Chat now
Available to paid subscribers. Get instant answers to your mechanical reference questions.