How much pressure should R 134 AC system have?

The pressure for an R-134a AC system typically varies based on the ambient temperature. Generally, at 70°F (21°C), the low side pressure should be around 25-45 psi, while the high side pressure should be between 150-250 psi. However, it's essential to consult the vehicle's specific service manual for accurate pressure specifications, as these can differ based on the system design and refrigerant charge. Always ensure to check pressures under proper operating conditions for the best results.