Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1314

6E1–332

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

If Diagnostic Trouble Code P1121 cannot be duplicated,
reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help to determine how often

the condition that caused the Diagnostic Trouble Code to
be set occurs. This may assist in diagnosing the
condition.

DTC P1121 – TP Sensor Circuit Intermittent High Voltage

Step

Action

Value(s)

Yes

Was the ”On–Board Diagnostic (OBD) System Check”
performed?

—

Go to Step 2

Go to OBD

System

Check

Is Diagnostic Trouble Code P0123 also set?

—

Go to DTC

P0123 first

Go to Step 3

Is Diagnostic Trouble Code P0463 and/or P1106 also
set?

—

Go to Step 6

Go to Step 4

Check for a poor sensor ground circuit terminal
connection at the TP sensor.

Was a problem found?

—

Go to Step 9

Go to Step 5

Check the TP signal circuit between the TP sensor
connector and the PCM for an intermittent short to
voltage.

Was a problem found?

—

Go to Step

Go to Step 8

Check for an intermittent short to voltage on the 5 volt
reference circuit between the PCM and the following
components:

MAP Sensor

EGR Position Sensor

Was a problem found?

—

Go to Step

Go to Step 7

Check for a poor sensor ground terminal connection at
the PCM.

Was a problem found?

—

Go to Step 9

Go to Step 8

Check for an intermittent open or a faulty splice in the
sensor ground circuit.

Was a problem found? (if no, start with the diagnosis
chart for other sensors in the circuit and see if 5V
returns.)

—

Go to Step

Refer to

Diagnostic

Aids

Replace the faulty harness connector terminal for the
sensor ground circuit.

Is the action complete?

—

Verify repair

—

Repair intermittent open/short circuit in wiring harness
as necessary.

Is the action complete?

—

Verify repair

—

6E1–333

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P1122 THROTTLE POSITION (TP)

SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE

060R100029

Circuit Description

The throttle position (TP) sensor circuit provides a voltage
signal that changes relative to the throttle blade angle.
The signal voltage will vary from less than 1 volt at closed
throttle to more than 4 volts at wide open throttle (WOT).
The TP signal is used by the powertrain control module
(PCM) for fuel control and for most of the PCM controlled
outputs. If the PCM detects a TP signal that is
intermittently above the range of the TP sensor,
Diagnostic Trouble Code P1122 will be set. DTC P1122 is
a type D code.

Conditions for Setting the DTC

The ignition is ON.

TP sensor indicates a throttle position signal
intermittently less than 0.235 volt. The above
conditions are met for 20 test failures within 200 test
samples.

Action Taken When the DTC Sets

The PCM will not illuminate the malfunction indicator
lamp (MIL).

The PCM will store conditions which were present
when the Diagnostic Trouble Code set as Failure
Records data only. This information will not be stored
as Freeze Frame data.

Conditions for Clearing the DTC

A history Diagnostic Trouble Code P1122 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

Diagnostic Trouble Code P1122 can be cleared by
using the Scan Tool’s ”Clear Info” function or by
disconnecting the PCM battery feed.

Diagnostic Aids

Check for the following conditions:

Poor connection at PCM – Inspect the harness
connectors for backed–out terminals, improper
mating, broken locks, improperly formed or damaged
terminals, and poor terminal–to–wire connection.

Damaged harness – Inspect the wiring harness for
damage; shorts to ground, shorts to battery positive,
and open circuits. If the harness appears to be OK,
observe the throttle position display on the Tech 2 while
moving connectors and wiring harnesses related to the
TP sensor. A change in the display will indicate the
location of the fault.

The TP sensor shares a 5 Volt reference with the MAP
sensor and Fuel Pressure sensor.
If these codes are also set, it could indicate a
problem with the 5 Volt reference circuit or
components itself.

The TP sensor share a ground with the ECT, the CKP,
the CMP and the automatic transmission position
sensor and the Fuel Pressure sensor.

6E1–334

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help to determine how often
the condition that caused the Diagnostic Trouble Code to

be set occurs. This may assist in diagnosing the
condition.

DTC P1122 – TP Sensor Circuit Intermittent Low Voltage

Step

Action

Value(s)

Yes

Was the ”On–Board Diagnostic (OBD) System Check”
performed?

—

Go to Step 2

Go to OBD

System

Check

Is DTC P0122 also set?

—

Go to DTC

P0122 first

Go to Step 3

Is DTC P1107 and/or P0462 also set?

—

Go to Step 6

Go to Step 4

Check for a poor 5 volt reference circuit or TP signal
circuit terminal connection at the TP sensor.

Was a problem found?

—

Go to Step 9

Go to Step 5

Check the TP signal circuit between the TP sensor
connector and the PCM for an intermittent short to
ground.

Was a problem found?

—

Go to Step

Go to Step 8

Check for an intermittent short to ground on the 5 volt
reference circuit between the PCM and the following
components:

EGR Position Sensor

MAP Sensor

Was a problem found?

—

Go to Step 9

Go to Step 8

Check for a poor 5 volt reference circuit terminal
connection at the PCM.

Was a problem found?

—

Go to Step 9

Go to Step 8

Check for an intermittent open or a faulty splice in the 5
volt reference circuit.

Was a problem found? (if no, start with the diagnosis
chart for other sensors in the circuit and see if 5V
returns.)

—

Go to Step

Refer to

Diagnostic

Aids

Replace the faulty harness connector terminal(s) for
the 5 volt reference circuit and/or the TP signal circuit
as necessary.

Is the action complete?

—

Repair

complete. If a

driveability

symptom still

exists, refer

to Symptoms.

—

Repair intermittent open/short circuit in wiring harness
as necessary.

Is the action complete?

—

Repair

complete. If a

driveability

symptom still

exists, refer

to Symptoms.

—

6E1–335

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC)

P1133 O2 SENSOR INSUFFICIENT SWITCHING (BANK 1 SENSOR 1)

060R100030

Circuit Description

The powertrain control module (PCM) monitors the
heated oxygen sensor (HO2S) activity for 90 seconds
after ”Closed Loop” has been enabled. During this test
period the PCM counts the number of times that the
HO2S signal voltage crosses the rich–to–lean and
lean–to–rich threshold. If the PCM determines that the
HO2S did not switch enough times, Diagnostic Trouble
Code P1133 will be set.
A lean–to–rich switch is determined when the HO2S
voltage changes above and below 450 mV. DTC P1133 is
a type B code.

Conditions for Setting the DTC

No MAP, IAT, ECT, TPS, Fuel Trim, Injector, Misfire,
CKP, EGR, EVAP Diagnostic Trouble Codes are
present.

Engine coolant temperature (ECT) is above 60

(140

F).

Engine is operating in ”Closed Loop”.

The engine has been running at least two minutes.

Canister purge duty cycle is greater than 2%.

Calculated air flow between 17 and 32 grams/sec.

Engine speed is between 1500 RPM and 3500 RPM.

Above conditions are present for 1 second.

sensor transitions crossing 0.3–0.6 V.

90 seconds after ”Closed Loop” and has been
achieved, the PCM monitors the oxygen sensor as it

switches above and below 450 mV. If fewer than 22
rich–to–lean and 22 lean–to–rich switches are
detected, Diagnostic Trouble Code P1133 will be set.

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

”Open Loop” fuel control will be in effect.

The PCM will store conditions which were present
when the Diagnostic Trouble Code was set as Freeze
Frame and in the Failure Records data.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL OFF on the third consecutive
trip cycle during which the diagnostic has been run and
the fault condition is no longer present.

A history Diagnostic Trouble Code P1133 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.

Diagnostic Trouble Code P1133 can be cleared by
using the Scan Tool’s ”Clear Info” function.

Diagnostic Aids

A malfunction in the HO2S heater ignition feed or ground
circuit may cause a Diagnostic Trouble Code P1133 to
set. Check HO2S heater circuitry for intermittent faults or
poor connections. If connections and wiring are OK and

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