What Does P0398 Mean?
This code is in the reserved/manufacturer-specific range near the camshaft position sensor codes for bank 2. When defined, it typically relates to a camshaft position sensor performance or rationality fault on bank 2. The ECM has detected that the camshaft position signal does not correlate properly with expected engine parameters. The driver may experience rough running, reduced power, or difficulty starting.
Common Causes
32%
Camshaft position sensor failure — output signal out of expected range or pattern
28%
Timing chain or belt has jumped one or more teeth, altering cam-to-crank relationship
20%
Wiring fault in the sensor circuit — open, short, or high resistance
12%
VVT solenoid stuck or malfunctioning, causing incorrect cam phasing
8%
Low or contaminated engine oil affecting VVT system operation
Diagnostic Steps
1
Check freeze frame data and note engine RPM, coolant temperature, and calculated load at the time of fault — determine if this is a cold-start or warm-running issue.
2
Verify cam-to-crank signal correlation using a dual-trace oscilloscope — the relationship should be consistent and match manufacturer specifications for timing offset.
3
Inspect the sensor wiring and connector for damage, corrosion, or oil contamination. Measure circuit resistance and compare to specifications.
4
If VVT-equipped, command the VVT solenoid on and off using bidirectional scan tool control while monitoring cam position change — verify full range of authority.
5
Check engine oil level and condition — low oil level or sludge can impair VVT actuator operation, causing cam position faults.
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
This code is in the reserved/manufacturer-specific range near the camshaft position sensor codes for bank 2. When defined, it typically relates to a camshaft position sensor performance or rationality fault on bank 2. The ECM has detected that the camshaft position signal does not correlate properly...
The most common cause of P0398 () is: Camshaft position sensor failure — output signal out of expected range or pattern
Typical repair costs for P0398 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
If timing has jumped, continued driving risks severe engine damage from piston-to-valve contact (interference engines). If the engine runs roughly or makes unusual noises, do not drive — have it towed. If it runs smoothly with just the MIL on, short trips to a shop are acceptable.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0398 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Timing / Variable Valve Timing
Difficulty
Type
Generic (SAE)
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