Twin Port Opel and the Р1113 Error

Specialists of Russian automobile repair shops know that though cars of foreign manufacture for the most part are different from domestic cars in terms of assembly quality and comfort level, they can equally have “congenital” design defects and intrinsic problems.

One such “disease” is a Р1113 error on Opel cars with a Z16XEP engine. It happens so often that we can safely say that 80-90% of cases when a Check Engine light is on in cars equipped with these motors are due to the cause of this very error. A dealer scanner decodes it as “Port Deactivation Position Sensor Circuit Low Voltage“. Or “P1113 Intake Resonance Switchover Solenoid Control Circuit”.

Before continuing the discussion, let us explain what device we’re talking about here and what we mean by “port”.

Engine designers are dealing with a variety of mutually exclusive requirements. On the one hand, the engine must develop a sufficient power; on the other hand, it should consume as little fuel as possible; on the third hand, it must comply with high environmental requirements.

The solution to all these challenges includes, but is not limited to, optimization of the cylinder air filling process. However, here is a contradiction as well: to ensure maximum cylinder filling in the full-load mode, the exhaust system section should be increased, but during operation at low speeds, a large section of intake ports leads to decreased air flow speed and thus to low turbulence in the mixture coming into the cylinders. As a result, torque decreases at low engine speed when the sectional area of intake ports increases.

A simple and beautiful solution was found for this problem.

Since the majority of modern-day engines are multi-valve engines, the design provides for an individual port for each intake valve of the pair. A butterfly damper (6) is installed in one of ports. Dampers on all of the cylinders open simultaneously, for which a single rod and servo (4) are intended. At high speed and high load, the dampers are open; the air flow in this situation enters the cylinder via two ports (1) at the same time, and the filling is efficient.

During operation at low speed, the dampers (6) close, the air flow speed in the port (3) increases, which results in noticeably increased turbulence in the mixture (2) coming into the cylinders. Due to the turbulence, not only the homogeneity and combustion of the mixture improve, but the exhaust gas recirculation rate also increased considerably and, due to this, decreased pump losses and fuel consumption also become possible. And certainly, the charge temperature decreases, causing the amount of nitrogen oxides in the exhaust gas composition to drop significantly.

Such a design has been implemented by several car manufacturers:

  • Intake Manifold Runner Control (IMRC), Charge Motion Control Valve (CMCV) - Ford
  • Twin Port - Opel
  • Variable Intake System (VIS) - Toyota
  • Variable Induction System (VIS) - Volvo

Let us look at the Opel design, the so-called Twin Port. All the system parts are concentrated in a special flange installed between the cylinder head and the intake manifold. Each intake port in it is divided into two isolated ports leading to the valves. One of these ports can be shut off by a damper. This is the “port” mentioned in description of the fault code.

A vacuum actuator serves to move the dampers. It is controlled, in turn, using an electric valve connected to the electronic engine control unit. A potentiometer-type sensor mechanically connected to the damper rod is responsible for monitoring command execution and current damper positions. This is the sensor mentioned in the description of code Р1113: “Port Deactivation Position Sensor Circuit Low Voltage“.

Diagnosing the problem diagnostics is not difficult. Connect the scanner, go into the Data Stream, and find there the voltage from the sensor. If there is a P1113 error, it is usually about 0.1 V.

Next, open the hood, pass your hand underneath the intake manifold, feel the damper drive rod, and press it with your finger. If the voltage increases smoothly by approximately 5 V, the sensor and its circuits are in good condition.

Parts for the Twin Port assembly are not supplied separately, and the manufacturer recommends replacing the entire assembly. This is done on cars under warrant, but owners of out-of-warrant cars do not agree to have the assembly replaced because of its high price, about 25,000 rubles. Therefore, less expensive solutions to the problem must be found.

Many variants have been suggested on the Internet:

  • Installation of an additional resistor in the sensor ground circuit
  • Drilling out the sensor attachment holes and rotating the sensor about its axis
  • Replacement of the bushing abutting the damper drive rod with a larger-diameter bushing

You can try to replace the sensor, but it doesn’t always work. To perform most of these operations, access from beneath is required, necessitated the removal of the starter, which surely involves additional difficulties.

A novel “people’s” method was suggested by Yury Mikhaylovich Khokhlov, a diagnostician at a Saint-Petersburg GM dealership.

Let’s give him the floor to speak: “I removed the corrugation from the air filter to the throttle assembly; beneath it there is the vacuum actuator for the Twin Port system’s rod. It is attached with two screws, the front one is short and the rear one is long.

“I removed the front screw and loosened the rear one. I turned the vacuum actuator about the rear screw until the sensor voltage on the scanner reached 0.5 V. Then I tightened the rear screw and checked the tightening by swinging the actuator. The front screw didn’t fit into place, we would do without it! I put the corrugation back in place.

“That’s all! For several years, the Р1113 error has been eliminated in dozens of cars; there have been no returns”.