DTC 1-4-3

FB. Fault code 1-4-3 Rex-I

* 1-4-3 Knock sensor signal absent or faulty



Conditions for fault code:
With a hot engine and engine speeds above 2000 rpm, a test is carried out of the signal from the knock sensor. If the signal is below a certain level, the ignition is retarded and fault code 1-4-3 is set.
Since the signal from the knock sensor cannot be measured without special equipment, only the wires are measured.

Causes of fault:
Break or short circuit to ground in wires or knock sensor. Connection resistance in contacts.

Fault symptoms:
Poor acceleration.

FB1




Connection of measurement box
Connect the measurement box to Rex-I and check the chassis connection according to N3-N4. N. Measurement Box, Signal Description
^ Continue with Checking of wires leading to knock sensor FB2

FB2




Checking of wires leading to knock sensor
- Ignition off.
- Remove the connector from the knock sensor and bridge the connections in the connector.
Connect an ohmmeter between #12 and #13.
The ohmmeter should show approx. 0 ohms.

If the value differs:
^ Check the wires between the control unit and sensor for breakage and connection resistance according to CD. CD. Checking of Wiring

- Disconnect the bridge.
Connect an ohmmeter between #13 and #20 (ground).
The ohmmeter should show infinite resistance.

If the value Is OK:
Intermittent fault.
^ Check the connectors for loose connection according to CD. CD. Checking of Wiring

If the value differs:
^ Check the wire between the control unit and sensor for short circuit according to CD. CD. Checking of Wiring