Oxygen sensors do not last forever. You both have declared oxygen sensor faults. First change the sensors - that may be the full sum of your problems.
The RB413 engine in the WagonR+ normally has two sensors, both the same Part No. (18213-83E00). One in the exhaust manifold, and one in the front exhaust pipe. If only one is faulty, it is likely to be the first.
However, one variant has only one sensor, in the manifold, and vehicles with VIN ending 280001 and above have two different sensors, which are different to the one numbered above. (18213-86G00 and 18213-86G10). From the test data, it appears that the front sensor is electrically different to the rear, which is similar to the sensor used in the first case.