Error Code P0892 is defined as TCM power relay sense circuit intermittent. This is a generic trouble code, meaning it applies to all cars with the OBD-II system, especially those made since 1996 up to present. This includes cars from, but not limited to Chrysler, Dodge, Ford, Hyundai, Kia, Jeep, and Smart. However, it seems to be more common among Honda cars.
Suppose a 2017 Ford Fiesta hatchback stores Error Code P0892 with Malfunction Indicator Lamp (MIL) lit up. In that case, that means the Powertrain Control Module (PCM) has determined an intermittent voltage problem in the TCM power relay control circuit.
While some TCM in OBD-II equipped modules are built into the PCM, most are stand-alone components. Depending on your 2017 Ford Fiesta hatchback make and model, codes that start with P, B, and U are related to TCM. For this error code, there’s a strong chance there are other related PCM or TCM codes as well.
The Controller Area Network (CAN) is a sophisticated system of connectors and wirings that works by transmitting data between the PCM and TCM. The data (including stored codes) may also be shared with other controllers through CAN. RPM (transmission input and output speed), wheel speed, and 2017 Ford Fiesta hatchback speed are shared between multiple controllers. They’re used to compare electronic control systems, anti-lock braking systems, and electronic stability control systems. This code is unique as it’s usually only stored if there are other traction control system related codes. An electronic or mechanical problem may cause these codes.
Control modules are a network of computers that controls the electronic transmission control system in OBD-II equipped cars. This includes constant communication between different control modules through the CAN.
The PCM utilizes input signals from multiple engine and transmission sensors to calculate automatic transmission shift strategy. A high-pressure pump (inside the transmission) forces fluid through the valve body and into the sprag assembly; in addition to lubricating and cooling the transmission. The high-pressure fluid allows the clutches to separate from the sprag momentarily so that the gear ratio may be changed smoothly. One or more electronic pressure control (EPC) solenoids help to regulate fluid pressure. Electronic pressure (EP) sensors provide the PCM with pertinent data regarding fluid pressure at various points in the transmission. Electronic shift solenoids are used to interrupt the flow of high-pressure fluid so that the transmission shifts gears when commanded. The PCM uses voltage input signals from the transmission input speed sensor and transmission output speed sensor to determine if the transmission is shifting efficiently.
If the PCM sees a problem that demands the illumination of the Check Engine light, this code will be stored.
As with most codes, you need a diagnostic scanner, DVOM (digital volt/ohmmeter) and a reliable 2017 Ford Fiesta hatchback information source that shows how to diagnose the code. An oscilloscope can also help in diagnosing various speed sensors.
You can save time by looking for a TSB (technical service bulletin) that shows similar error code, year, make and model, engine, and symptoms. You may find this info in a 2017 Ford Fiesta hatchback information source.
First, you need to retrieve all the stored codes and the pertinent freeze frame data by connecting the scanner to your 2017 Ford Fiesta hatchback’s diagnostic port. Then, make sure you clear the codes before taking your 2017 Ford Fiesta hatchback for a test drive. One of two things must occur in your test drive; the error code restored, or the PCM enters readiness mode.
The problem is intermittent if the PCM enters readiness mode. This means you may need to wait for the situation to worsen before you can diagnose it accurately. If the code is restored, then you can proceed with your diagnosis.
Use your 2017 Ford Fiesta hatchback information source for the diagnostic flow chart, face views, component locator charts, connector pinout charts, and wirings diagram.
Next, inspect all related connectors and wirings. Replace or repair any damaged components.
Then, test the voltage and ground circuits of TCM and PCM using the DVOM. Also, check the system fuses. Replace any blown or defective fuses, retest as needed.
If there are both voltage and ground at the TCM, test the corresponding circuit at the PCM connector. No voltage means there’s an open circuit between the PCM and the component in question. If there is voltage, you can suspect a programming error, or a defective PCM or TCM.
The transmission may start to shift harshly when this code is stored.
If your 2017 Ford Fiesta hatchback shows this code, it must be addressed as soon as possible. And since the traction control is in problem, it is important to avoid wet, slippery, or rugged surfaces.
This code is usually stored due to a defective contact relay.