California median pay
$73,950 a year
National median
$61,770
Diesel techs in California
About 23,500
Must-know skill
Emissions systems
Diesel technicians keep California’s trucks, buses and heavy equipment running. The state pays them about $12,000 more than the national median, and the work is steady: California expects about 2,040 openings a year. What makes California different is emissions. The state has the toughest truck emissions rules in the country, and techs who understand them are in demand.
From the dean’s desk
Diesel is pretty straightforward all across the country, but you have to get a firm grasp on the emissions stuff. That’s the most important.
— Lester Burkes, Dean of Trades, Transportation & Apprenticeship
Why emissions knowledge matters in California
Modern diesel engines rely on aftertreatment systems such as diesel particulate filters (DPF), selective catalytic reduction (SCR) with diesel exhaust fluid, and EGR, all monitored by on-board diagnostics (OBD). When those systems fail, trucks lose power or get sidelined, and fleets need techs who can diagnose them.
California also requires periodic emissions testing for most heavy-duty trucks through the California Air Resources Board’s (CARB) Clean Truck Check program. Tests are done by credentialed testers, who complete a roughly two-hour CARB training course, pass a 20-question exam with at least 80%, and renew every two years. Becoming a credentialed tester is a practical way for a new tech to add value to a fleet or shop.
Where to train in California
- Community college diesel programs: schools such as Fresno City College (medium/heavy-duty truck) and San Joaquin Delta College (Diesel Equipment Technician) offer certificates and degrees.
- Apprenticeships: some colleges and employers run registered diesel apprenticeships, such as Long Beach City College’s heavy-duty diesel apprenticeship.
- Dealer and fleet training: truck dealers, transit agencies and large fleets often hire entry-level techs and train them on their equipment.
New openings are posted every week on our California apprenticeship openings tracker.
Ask any program how much shop time you’ll get, whether it covers aftertreatment and OBD diagnostics, and where graduates are working. ASE’s medium/heavy truck tests (T-series) are a good goal once you have experience.
What diesel techs earn in California
California diesel techs earned a median of $73,950 in May 2025, compared with $61,770 nationally. The Bay Area pays the most.
| Area | Median pay (May 2025) | Hourly |
|---|---|---|
| San Jose–Sunnyvale–Santa Clara | $88,980 | $42.78 |
| San Francisco–Oakland–Fremont | $82,100 | $39.47 |
| Los Angeles–Long Beach–Anaheim | $77,380 | $37.20 |
| Modesto | $76,640 | $36.85 |
| San Diego–Chula Vista–Carlsbad | $75,070 | $36.09 |
| Sacramento–Roseville–Folsom | $72,660 | $34.93 |
| Riverside–San Bernardino–Ontario | $71,300 | $34.28 |
| Fresno | $65,210 | $31.35 |
| Bakersfield–Delano | $63,520 | $30.54 |
| California overall | $73,950 | $35.55 |
| United States | $61,770 | $29.70 |
Diesel jobs in California are projected to grow about 5% from 2024 to 2034.
Steps to become a diesel tech in California
1
Finish high school or a GED
Mechanical, electrical and math skills all help.
2
Train in a diesel program or apprenticeship
Make sure it covers electrical diagnostics and aftertreatment.
3
Get hired and learn on the job
Dealers, fleets, transit agencies and equipment companies all hire diesel techs.
4
Master emissions systems
Learn DPF, SCR, EGR and OBD diagnostics, and consider becoming a CARB Clean Truck Check credentialed tester.
5
Earn ASE truck certifications
Add T-series certifications as you build experience.
Frequently asked questions
Do diesel techs need a license in California?
No state license is required to work as a diesel tech. To perform Clean Truck Check emissions tests, you need a CARB tester credential.
How much do diesel mechanics make in California?
The median was $73,950 a year in May 2025, and close to $89,000 in the San Jose area.
What should new diesel techs focus on?
Emissions systems. Aftertreatment and OBD diagnostics are where California fleets need the most help.
Sources
- CARB: Clean Truck Check credentialed tester overview
- Fresno City College: Diesel technology
- Long Beach City College: Heavy-duty diesel apprenticeship
- BLS Occupational Outlook Handbook: Diesel Service Technicians
- O*NET OnLine: Diesel tech wages and outlook in California (BLS OEWS May 2025)
Related: Top 10 Diesel Careers · Diesel Mechanic in Washington · All California guides
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