YH4
GRAND
VITARA
7B1-20 AUTOMATIC TRANSMISSION (4 A / T)
PRECAUTION IN DIAGNOSING TROUBLE
Don't disconnect couplers from PCM (ECM), battery cable from battery, PCM ground wire harness from engine
or main fuse before checking the diagnosis information (DTC, freeze frame data, etc.) stored in PCM memory.
Such disconnection will clear memorized information in PCM memory.
Using SUZUKI scan tool (Tech-1), or also generic scan tool for vehicle without monitor connector, the diagnostic
information stored in PCM memory can be checked and cleared as well. Before its use, be sure to read Operator's
(instruction) Manual supplied with it carefully to have good understanding of its functions and usage.
Priorities for diagnosing troubles (Only for vehicle without monitor connector)
If two or more diagnostic trouble codes (DTCs) are stored, proceed to the flow table of the DTC which was de-
tected earliest in the order and follow the instruction in that table.
If no instructions are given, troubleshoot diagnostic trouble codes according to the following priorities.
1. Diagnostic trouble codes (DTCs) other than DTC P0171 / P0172 (Fuel system too lean / too rich) and DTC
P0400 (EGR flow malfunction)
2. DTC P0171 / P0172 (Fuel system too lean / too rich) and DTC P0400 (EGR flow malfunction)
Be sure to read ªPrecautions for Electrical Circuit Serviceº in Section 0A before inspection and observe what is
written there.
PCM replacement
When substituting a known-good PCM, check for following conditions.
Neglecting this check may result in damage to good PCM.
± All relays and actuators have resistance of specified value.
± MAF sensor, MDP sensor, TP sensor and fuel tank pressure sensor are in good condition. Also, the power
circuit of these sensors is not shorted to the ground.
