What does it mean?
Code P0013 is defined as “Camshaft position (CMP) actuator, exhaust/right/rear, bank 1 circuit malfunction”, and is set when a fault is detected in the electrical circuit that controls the variable valve/cam timing system. Code P0013 relates to the B, or exhaust camshaft on Bank 1, which is the set of cylinders on one side of an engine that contains cylinder #1. The function of variable valve timing is to enable engines to develop more torque under different operating conditions.
For instance, valve/cam timing can be retarded at high engine speeds to increase power output, and to reduce harmful exhaust emissions such as nitrous oxide. When the system advances valve/cam timing, fuel economy is improved under light engine loads. In terms of the system’s operation, valve/cam timing is either advanced or retarded by the action of pressurized oil on a mechanism that forms part of the camshaft.
Design specifics vary from system to system but in principle, the pressurized oil acts on an actuator to rotate the camshaft either clock-wise, or counter-clockwise relative to a base timing position to advance or retard the valve timing, depending on operating conditions such as varying loads on the engine, and throttle inputs from the driver. The image below shows a typical oil flow control valve, with the solenoid and electrical connector making up the top part of the assembly.
Note the fine wire mesh screens on the bottom part. These are essential to prevent solid particulate matter in the oil from interfering with the operation of the actuator on the camshaft. Note: “Circuit Malfunction” indicates that there is a malfunction in the control circuit, as opposed to a fault in a sensor or other component.
With “Circuit Malfunction” codes, replacement of sensors and components in the affected circuit will almost never resolve the problem, since as the code suggests, the trouble is in the circuit . This distinction between “circuit” and “sensor/component” is a great help to anyone trying to diagnose a circuit malfunction code, since it narrows the list of possible causes down considerably.
The causes of “Circuit Malfunction” codes are much the same as those for “Open Circuits” i.e., broken wiring, poor connections across electrical connectors or previously repaired wiring, loss of ground that prevents current flow, blown fuses, defective relays, faulty switches, or any of a host of other issues and problems that prevents a flow of current through wiring. Issues like high/low/intermittent voltages can set a “Circuit Malfunction” code on some applications.
Moreover, “Circuit Malfunction” codes could also indicate a problem with negative current control / flow, as well as issues with failed or failing PCM’s (Powertrain Control Modules), although control module failure is a rare event.