P25E7: B Camshaft Position - Unable to Achieve Locked Position Bank 2

What it means

Camshaft phaser B on bank 2 cannot reach its base position at engine shutdown so the lock pin never engages. Next cold start may run rough until oil pressure builds.

At a glance

• Usually lights the check-engine light

How it works

Bank 2 is the engine bank opposite bank 1, and its B camshaft is controlled by a phaser that changes valve timing. At shutdown, the module checks whether that phaser returns to its base position and locks; this code sets when it detects that the B phaser on bank 2 did not reach the locked position.

Common causes

Most likely first.

1. Worn vanes or housing inside the phaser
2. Sludge or contaminated oil prevents return to base
3. Oil control valve leaks internally

Symptoms

• Check engine light on
• Power loss especially in mid-rpm range
• Possible rough idle or stalling
• Increased fuel consumption

How to diagnose it

1. Check freeze-frame data and camshaft position readings for bank 2 at shutdown or the next cold start to confirm the B cam timing is the concern.
2. Check the engine oil level, condition, and service history because dirty or unsuitable oil can impede the phaser’s return.
3. Inspect the bank 2 B-phaser oil passages, connector, and wiring for contamination, damage, or poor connections.
4. Use scan-tool data to compare commanded and actual B cam angle on bank 2 during shutdown and startup.
5. Test the bank 2 B-phaser oil control valve for internal leakage or sticking, then assess the phaser’s return and locking action if the valve and oil supply are sound.

Common fixes

• Correct the oil level and replace contaminated or unsuitable oil and filter.
• Clean or repair restricted oil passages feeding the bank 2 B phaser.
• Repair or replace a sticking or internally leaking B-phaser oil control valve on bank 2.
• Replace the worn bank 2 B camshaft phaser if it cannot return and lock.

Can I keep driving?

Avoid hard acceleration if the engine runs roughly, stalls, or loses power; continued operation can worsen drivability and fuel economy. If stalling makes the vehicle difficult to control, stop driving and arrange repair.