P01CA: Fuel Rail Pressure Too Low - Engine Cranking Bank 2

Some V engines have a separate high-pressure fuel circuit per bank, each with its own pump or rail – for example Audi's 4.0 TFSI V8 with a second high-pressure pump for bank 2. These codes are the bank 2 counterparts of the system pressure codes for bank 1. P01CA is the bank 2 counterpart of P00C6: during cranking the rail pressure on bank 2 does not rise quickly enough to the minimum needed to release injection. For bank 1 GM checks once per start that pressure exceeds about 3 MPa and does not fall below 2 MPa, with two trips. No manufacturer using exactly this code was found; GM's two-rail LT6 reports the same situation with the bank-neutral P00C6.

Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines.

Symptoms

• Check engine light on
• Long cranking or no start
• Rough running right after start

Most likely causes

• High-pressure pump of bank 2 or its drive weak
• Low supply pressure at start (lift pump, check valve)
• Leak or leaking injector on bank 2
• Bank 2 rail pressure sensor or connector

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the pump's fuse, relay, and connector
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Replace the filter if it is due for maintenance
4. Compare commanded and actual pressure in live data
5. Measure the pressure with a suitable gauge
6. Check the sensor and regulator before replacing the pump

Good to know

• Repair difficulty: hard
• It affects emissions.

What each character of P01CA means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 1: Air and fuel
• CA: Specific fault in that system

Frequently asked questions

Can I keep driving with code P01CA?

Avoid long trips and hard acceleration. If you smell fuel or the car stalls, do not continue.

What causes code P01CA?

The most common causes are: high-pressure pump of bank 2 or its drive weak; low supply pressure at start (lift pump, check valve); leak or leaking injector on bank 2.

Related codes

• P00C6Fuel Rail Pressure Too Low - Engine Cranking
• P01C8Fuel Rail/System Pressure - Too Low Bank 2
• P01C9Fuel Rail/System Pressure - Too High Bank 2
• P01BFFuel Rail Pressure Sensor Circuit Range/Performance Bank 2

Sources

• law.cornell.edu: 13 CCR 1968.2
• saabwisonline.com: dtc p0089 p00c6 p228c or p228d lf1 lfw
• gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
• static.nhtsa.gov: MC 11009469 0001

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.