P1923
Read the instructions below then
start the fault diagnostic procedure.
Symptom: Some of the following symptoms may be observed:
Engine will not start.
CHECK ENGINE.
Automatic transmission not shifting gear.
CHECK GEARBOX.
Additional trouble codes in Trionic (P1624 or P1908).
DTC P1921 or P1902 in TCM (if TCM can be contacted).
No Bus Data From TCM. See Fault Tracing 3:5 Bus and Diagnostic Communication.
Fault symptoms
Some of the following symptoms may be observed:
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Automatic transmission not shifting gear.
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Additional trouble codes in Trionic (P1624 or P1908).
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DTC P1921 or P1902 in TCM (if TCM can be contacted).
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On-Board Diagnostics
Type of diagnosis:
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Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.
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Enable criteria:
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Engine running. TCM has previously been on the bus on some occasion.
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Fault criteria:
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No communication for more than 3 s.
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Dependents:
System reaction to a fault:
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Max. engine torque (Bus from TCM) set to 310 Nm.
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OK report:
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Enable criteria fulfilled and fault criteria not fulfilled within 60 s.
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Fault handling:
(See section
Fault handling III, other emission-related components and functions
for more information.)
Diagnostic help
Fault diagnosis concerns an intermittent electrical fault in the power supply to the transmitting control module or any of the bus leads.
Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.
